Is evil a perception or is it something that is objective?
Here's my line of thought on it: "If evil were a perception then the law would be moot to some extent. However, if evil were objective then would that advocate for absolute morality?"
Todd Calder distinguishes between a broad concept of evil which would be any bad state of affairs resulting from either natural causes or moral agents and a narrow concept:
In contrast to the broad concept of evil, the narrow concept of evil picks out only the most morally despicable sorts of actions, characters, events, etc....Since the narrow concept of evil involves moral condemnation, it is appropriately ascribed only to moral agents and their actions. For example, if only human beings are moral agents, then only human beings can perform evil actions. Evil in this narrower sense is more often meant when the term ‘evil’ is used in contemporary moral, political, and legal contexts.
This narrow concept is what the OP appears to be interested in when asking about law and morality:
If evil were a perception then the law would be moot to some extent. However, if evil were objective then would that advocate for absolute morality?
Evil as a perception may be viewed as the position taken by "evil-skeptics". They "believe we should abandon the concept of evil" although they do not generally reject "other moral concepts, such as right, wrong, good, and bad". Calder summarizes their arguments:
Evil-skeptics give three main reasons to abandon the concept of evil: (1) the concept of evil involves unwarranted metaphysical commitments to dark spirits, the supernatural, or the devil; (2) the concept of evil is useless because it lacks explanatory power; and (3) the concept of evil can be harmful or dangerous when used in moral, political, and legal contexts, and so, it should not be used in those contexts, if at all.
Calder identifies Nietzsche as a famous evil-skeptic.
Those arguing for an opposing view, "evil-revivalism", claim the concept of evil usefully focuses attention on the "worst sorts of moral wrongs" to prioritize understanding of them so something can be done about them. They (such as Claudia Card and John Kekes) would claim it may be "more dangerous to ignore evil than to try to understand it".
So a partial answer to the OP's question would be to consider the alternatives provided by evil-skeptics and evil-revivalists. However, that doesn't answer the question about whether accepting evil implies the existence of "absolute morality". This may be something that evil-skeptics and evil-revivalists both want to avoid in trying to avoid supernatural explanations.
One might question whether there are positions besides the evil-skeptic and evil-revivalist positions that also address absolute morality. One may view absolute morality as characterized by moral obligation seen as an obligation to a deity. This deity would give absolute morality its "absolute" characteristic. This deity, however, introduces the supernatural that both evil-skeptics and evil-revivalists want to avoid.
One position that does this indirectly may be that of G. E. M. Anscombe in "Modern Moral Philosophy". She argues with the evil-skeptics that moral obligation necessitates the existence of the supernatural or at least the efforts of modern moral philosophers have not successfully developed "an adequate philosophy of psychology" that removes the need for such a supernatural lawgiver. But she argues against both in claiming their moral positions "are only harmful without" this obligation to a supernatural lawgiver that they both want to avoid.
Adding philosophers such as Anscombe would help cover the concept of absolute morality, viewed as moral obligation, in making a choice between which positions one wants to pursue.
Anscombe, G. E. M. (1958). Modern moral philosophy. Philosophy, 33(124), 1-19. https://www.pitt.edu/~mthompso/readings/mmp.pdf
Calder, Todd, "The Concept of Evil", The Stanford Encyclopedia of Philosophy (Fall 2018 Edition), Edward N. Zalta (ed.), URL = https://plato.stanford.edu/archives/fall2018/entries/concept-evil/.
'Evil', just like the concepts of 'Good' and 'Bad' is a matter of perspective.
Even though it associated with something negative, it does not mean it is always so objectively speaking.
Social Example: If tribe 'A' comes in and occupies all fertile land near tribe 'B' (while not considering them evil or good), from their perspective, they did nothing wrong. They did a good thing to feed their families. From tribe B's perspective, that is an evil deed because it deprives tribe B of their resources.
Now tribe B decides to go and kill the 'evil' occupiers. They will do a good deed to save their food supply. When the attack will happen, tribe 'A' will consider tribe 'B' evil because they are being killed by them.
Moral example: By the same logic, does is justify to kill 1 person to save 1 million ? Is that a good deed (because we saved 1 million) or an evil deed (because we killed one) ? If we consider it good, is it still good if we need to kill 10 for the same reason ? What about 100 ? What about 999 999 ? Where do we draw the line ?
Such a thing cannot be morally objective, it can only be statistically objective, assuming complete information on the subject exists.
Religion example: from current Christian religion's point of view and that of it's followers there's an Evil entity called Satan. But from Satan's and followers point of view it is God who is a Tyrant and Satan the good guy who raised against oppression and tyranny. In a similar manner, some religions will state that the God of the others is evil and that theirs is the good one. Just because one religion has more followers does not make it any better than another.
Political example: During the Soviet era, Americans considered the Soviets 'evil' and Soviets considered Americans 'evil'. This unfortunately continues today between many countries. Just because one side had more countries than another, does not make that side more or less evil.
Let's think it even more interesting: from the Planet's perspective, humans are evil.
As for the law, that has nothing to do with the rest. The law is less and less based on morality, which currently leads to many bad implications, but this is another subject.
The evil immoral acts by Man & evil natural disasters that contribute to Man's misery and global warming, are the symptoms of the deadly disease God calls Sin.
It is the law of Sin & Death ( Entropy ), that God has deemed inevitably necessary. Man must do evil and evil must happen until God ends it. Shortly.
Our final goal is to exist, therefore, to survive. In order to survive, we've learned several rules, which can be categorized in multiple levels (moral, legal, political, etc.). In any of such domains, rules define what is good and what is bad (or evil) for the survival of the group. Such is the meaning of evil: something that risks existence or persistence.
For example: it is bad to steal, because it harms someone, and such event decreases the probabilities of his survival (even stealing a peanut reduces the probabilities of survival, of course, in a very small amount). Survival requires the whole group to be in its best state.
Good or bad (evil) are subjective assessments. Suppose a killer was sentenced to death. Subjectively, for all members of the group, his execution is a good fact. But for the killer himself, his own death is a bad/evil fact.
"Is evil a perception or is it something that is objective?
To me, "evil" is definitely not the opposite of "good", which is simply "bad". "Evil" is something larger and more complicated.
"Good" and "Bad" are subjective perceptions (e.g. pineapple on pizza). But, given arbitrary definitions of "good" and "bad", "evil" can be objectively detected.
Here's something I wrote about evil at least a dozen years ago:
Many people talk about good and evil as if they are opposites. But good and evil do not have opposite meanings; good and bad do.
When one thinks of evil as the opposite of good, one misses its real significance, making any discussion or argument related to it very difficult to resolve. An understanding of the real meaning of evil can simplify many seemingly complicated situations. Evil means something completely different from bad, and it is something that one can define and use without resorting to religious absolutes.
Any group of people can determine a set of things, ideas, concepts, etc. that they all consider good, and a similar set that they all consider bad. Different groups of people will almost certainly produce different sets, and many things will not receive agreement as to their classification, but any individual group can achieve consensus on reasonably large sets.
One can then define Evil as something that presents itself as good, but which in the long run does more bad than good. The idea, that if a little of something does good then a lot of it must do better, often makes this process even worse.
Sugar provides a trivial example. Almost anyone encountering sugar for the first time would call it good, and more of it even better. But one can easily misuse sugar, leading to malnutrition, tooth decay, obesity, diabetes, etc. Of course the evil doesn't come from the sugar itself, but from the mistaken belief in sugar's intrinsic goodness.
Though some people might disagree, one can find other common examples in PDF files, white flour, Kwanzaa, and the fluoridation of drinking water.
A More Serious Example
I don't remember where I first heard or read of this example; I certainly don't claim to have originated it. But given how my memory works, I haven't plagiarized the wording.
People Are Basically Good
I know of no religion that teaches that "people are basically good", yet over the last century or two this evil concept has infiltrated much of western society. Yes, on the surface it seems true, hearing it makes people feel better about themselves, those that believe it might behave better towards others, and initially the world might end up a nicer place in which to live. This of course makes it an ideal candidate for propagating evil, and (at least) four bad things that it conceals confirm this.
1. It's Not My Fault
If "people are basically good", why do people do bad things? Obviously because something external to them has interfered with their basic goodness. People steal because of poverty, they abuse children because of the abuse they themselves suffered as children, they habitually drink because they inherited alcoholism genes, they do all kinds of bad things because of society and their environment, not because they have any personal choice in the matter.
With this point of view, the concept of individual responsibility for one's actions goes out the window.
External forces, not individual choices, cause bad behaviour.
2. I Don't Need To Change
If "people are basically good", they won't improve themselves. Yes, they can check for and eliminate bad external influences, but the good side of their personalities themselves needs no work. No one needs to, and perhaps no one can, develop and improve their character.
Even worse, while parents and educators will teach children to recognize the signs of external badness and how to combat them (e.g. pollution and racism), they will fail to teach the children to develop good character, assuming they inherently have it already. This relates closely to another evil, the practice of perfectionism, in which one concentrates on removing negatives without ever considering positives.
Individuals must learn to struggle against society and other external forces, not against their own feelings or tendencies, which "are basically good" already.
3. I Know What Is Right
If "people are basically good", then humanity can eventually remove the external factors that cause bad behaviour, creating a eutopian society. For instance, if we could end poverty, most crime and violence would cease to exist. This view even eliminates the need for moral standards (in a religious context, it almost eliminates the need for God, as humanity can provide its own salvation).
In an immoral society, those people that violate the existing moral standard at least know that they have chosen to do so. But in an amoral society, one has no choice to make; one can have any behaviour or belief other than that of expressing a moral position.
No one needs to develop moral judgement since they "are basically good" already.
4. They Are Wrong
If "people are basically good", then certainly you yourself "are basically good". You might occasionally display bad attitudes because of outside influences, but generally you have only good thoughts and correct ideas. So when someone else's beliefs or actions don't match yours you will know for sure that they must have the wrong beliefs, and that their bad behaviour and attitude needs correcting. Similarly, all other people with beliefs like yours must also have achieved the one true view of the world. You must therefore support each other and enlarge the size and power of your group in order to defeat the external influences that still corrupt the less fortunate people.
With such a belief, there is no need to consider other people's views of the world or to reconsider one's own position.
There is one right way to live, and anyone that lives differently is wrong.
But People Really Aren't Basically Good (or Bad)
On the surface, people are basically good presents a good message. But beneath this evil concept lie messages promoting irresponsibility, selfish and lazy character, amorality, and intolerance.
In reality people can increase or decrease the good and bad attributes of their characters, they can make moral judgements and choose to do the right thing (or not). Developing one's character within a moral standard forms a significant part of most religions. One society's moral standards might differ from another's, and from a religious view one might consider all but one of them wrong, but to survive, any society requires a moral standard.
When a society turns into something amoral and self-righteous that denigrates personal responsibility and character, it can't survive long. And today's Americans wonder why, after receiving nearly two centuries of admiration, so much of the rest of the world now has so little respect for them.