To be sure, there are situations where there is some genuinely complicated moral situation. But that doesn't mean we have to pretend to be moral morons and sagely nod our heads and say "Yes, but Nazis thought they were right too, hmm, hmm."
Normative language used as shorthand for current consensus for whether the conflict was justified given the likely alternative outcomes for not engaging.
is learning and changing hypocrisy?
The problem, of course, is that belief. It’s catastrophically wrong. And it’s the sort of thing that black and white good vs evil thinking can lead you towards.
We can simultaneously say “the Nazis thought they were good” and “the Nazis were profoundly evil.” We can acknowledge the relativity of perspective without needing to apply a relativity of good and evil.
A necessary element of true goodness is a willingness to consider new ideas, a constant reevaluation of one’s beliefs, and an acknowledgment that the world is complicated and messy. Someone who does these things can justifiably conclude that they’re good and the other guys are evil, but you have to maintain that openness and reevaluation or you can slide into Good vs Evil where you can see no wrong on your own side, and that leads to disaster.