No human begin is morally perfect. My question is then, how can any one human being encourage another to improve their ways when that other person can always just reverse the question and ask "Why don't you do the same"?
For example, imagine if we have two people, say Claude and Raul. Claude is a psychopatic murderer who kills people for fun. He represents the ultimate evil. Raul is an ordinary person, he's not necessarily 'evil', but he does have moral imperfections such as selfishness and dishonesty.
Now imagine if Raul wants to encourage Claude to become a better person. How can Raul do this?
Raul attempts by saying this:
Raul: Clause, stop killing people. Can't you see how wrong that is?
Can't Claude just calmly respond with
Claude: Yes, Raul, it is very wrong. But so is being selfish, greedy, and dishonest. Why should I change my ways if you don't change yours?
What can Raul respond with here? I mean, obviously he might try to argue that, yes, it's not good to be dishonest or greedy, but it's much, much worse to kill people! But can't Claude still ignore the relativeness that Raul is trying to bring into the debate, and keep everything in absolute terms? For example by saying
Claude: Yes, I know it's much worse, but that's irrelevant. You are asking me to cause a moral shift in my behavior. I ask you why you are unwilling to do the same? Whatever answer you have to my inquiry, is the same answer I will give to your inquiry.
Hence, is Claude not immune to any argument Raul can throw at him, because by construction Claude will throw the same argument back?