Of course it's relevant. The things that drive a character's actions are always relevant. He thinks a world under total martial law where all of the lesser races are exterminated a select few pure blooded aryan Germans call the shots with him as fuhrer would be a better world. When you understand that, you work backwards from there to figure out how he got to that way of thinking, and through doing so you come to fully understand the character. Yes, he is motivated by hate. He's also motivated by fear of being powerless. And by a sense of nationalistic pride. And by the belief that fascism and racial elitism are the best way to go for the world over all. He's motivated by a lot of things, and there are a lot of different, although strongly intertwined in some places, causes for why he is motivated by those things. He's not a simple, one dimensional character. Yes, pretty much all of those dimensions are evil, but there are still layers there. Layers of reasons and experience and motivation. You can't just say "well, he's just motivated by this," because his actions and words have proved that he's motivated by other things too.