I would argue that it may be "possible" (or, rather, "non-problematic") in some cases, but that, as a general and practical consideration, no, it's not consistent.
Or, rather, it's not consistent to do that, for a given level of stakes in justifying the various beliefs in question.
Let me explain.
Because of reality, even the most deluded of people should have an intuitive understanding that there are things which are "true", and things which are not "true". Most of people would get familiar with this when reality places them in situation that they don't like. Ex: as a child, you fall down, and you get hurt. It's unpleasant. You'd rather not experience that. And yet you do. Clearly there is something out there, independent from you and from your preferences, that impacts you, whether you like it or not. You may decide to deny it, but if you do, sooner or later reality will catch up, and something bad will happen to you. Because of that, it was useful as far as evolution is concerned to develop a concept of truth, and to use it adequately to survive and thrive.
With that, we may define "truth" (at least in the frame of this discussion) as the property of a world model such that it allows to properly represent and make accurate prediction regarding reality.
Also, practically speaking, one way to be able to say that something is true is if it can be observed / measured independently from the observer and their own preferences.
So here we see that everyone (unless they are intellectually impaired maybe) should have an understanding a what "truth". Notably, "truth" is what allows them to navigate reality in order to achieve their goal and try to maximize their interest (or at least strive to do things or activities which ultimately "feel good"). That's why people don't like to be deceived. They understand, at least intuitively, that doing this to them causes them some kind of harm, insofar as it prevents them from achieving their goal, or from doing it optimally.
That's where we introduce the concept of stakes. The "level of harm" caused in the situation described above depends on how important it was for the person to achieve the goal in question. Lying to you about the schedule of the ice cream truck is "less bad" than accusing you of a serious crime that you did not commit in froint of a jury, because in the former case, the stakes are just the ability to get a sweet treat and the associated small pleasure, whereas in the latter case, the stakes are your ability to still spend your life as a free person, outside of prison (the stakes being here proportional to the number of years that you'd spend in jail if found guilty).
That's why truth, and establishing it properly, is so important in judicial matters, because the stakes of not punishing an innocent person, or to punish a guilty person only with a proportionate penalty, carry a lot of weight for the recipient.
So at this point we have defined a concept of truth, and a concept of stakes related to taking decision (based on beliefs).
Now, it should be easy for most people to understand that taking a decision based on a belief that is not true may lead to harm being caused to someone else, right?
Let's make the reasonable assumption that people don't like it when something bad happens to them or when they pay an opportunity cost (being prevented from achieving their goal) because someone took a decision based on a belief that is false (let's put aside for now the consideration that sometimes it's just very hard to know whether something is true or not / things may be uncertain, yet a decision must be taken). Ex: being falsely accused of murder.
Then, it seems like people should find it reasonable to decide that one of rules that needs to be followed when living in a society (as soon as there are two people or more) is that one should not do this (take a non-justified, harmful-for-someone-else decision), right? Of course, in practice, the application of this kind of "non-harm" rule is still subject to the balance between it and the individual stakes of the people. For instance, though I would still not like it, I would understand if someone were to falsely accuse me of murder, if the alternative for them was being killed by the real bad guy. The stakes for them (their own life) is in balance with, or even heavier than, the harm that they may cause to me.
Of course, such a rule is derived from an important axiom: the one that says that nobody is special, and so that the desire for people to "do what they want", and to be protected from adversity, is worth the same level of respect and consideration.
But then, why would people hold beliefs which they don't know are true in the first place? Well, there can be a lot of reasons.
Because it's convenient for them.
Because it makes them feel good.
Because they built their identity around it (and may not have had any choice in the matter in some cases, e.g. children).
Or maybe because it has never been important enough for them to validate or disprove properly (<=> because the stakes associated to that belief have never been high). After all, sometimes it hard to determine whether something is true or not, so it's understandable to hold some things for tentatively true until the times comes when it becomes important.
So then, we have seen / we can assume that:
- People can hold beliefs which are not true.
- People can harm other people by holding as true beliefs which are not.
- People don't like to be harmed in general, and in particular in that specific way.
- People can understand when one harms someone else, when the stakes for one is high enough, as long as the interests of everyone stay in balance.
So it follows that it's inconsistent to "hold for true a belief without enough justification with regards to the harm that may come to someone else from taking a decision based on that belief".
In more details, it's "fine" for one to believe in a supernatural being without reasonable evidence, as long as one does not make it someone else's problem, or, in general, as long as one does not create stakes for other people out of that yet-to-be-justified belief.
But I would argue that, for a non-negligible (or very vocal) proportion of the population, it's hard to do that, and sometimes they don't even care. For them, at least one of the hypotheses / considerations described above does not apply.
Maybe they consider themselves more important than other people, and that their interests trump that of other people (=> unbalance between their own interests and that of some other people, and less beholden to properly justifying their own beliefs compared to what they would ask other people to do if the roles were reversed). Maybe they lack the ability to put themselves in other people's shoes, in order to properly evaluate the balance of interests.
Or maybe they underestimate the potential of harm to other people associated to holding a belief as true when it's false or when it has not been demonstrated enough to be true.
Or maybe they are just wrong / deluded, and they let their own preferences impair their ability to reason regarding the topic which is the object of the belief.
So, to answer your questions:
- Given the importance of truth in order survive, strive, and achieve one's own goal, coupled with the need for people to live in society, and the understanding that no one is special, then no, it's not consistent.
- However, achieving truth is sometimes hard, so in practice it's understandable and "fine" to not do it, as long as the stakes are low.
- So, to use your words, the choice of the "method of justification" depends on the level of the stakes in achieving the truth for people who will be impacted by a decision taken based on the belief that is the object of the justification. I'd say that one way to evaluate this level is to try to put ourselves in the shoes of those people, and to actually ask them what those stakes are for them.