I am a very very lazy person. I like to pride myself on being in the running with Lebowski. And to me hate takes way way to much energy. Having even the simple idea of killing has to take some effort. Kind of seems like he just set out on a life not worth living IMO
Respectfully, do some reading of even middleschool level history books. He didn’t personally decide to “be mean” to particular groups. His worldview was shaped by the post WWI dynamics in Europe, latent stereotypes and domestic problems within Germany, and a whole lot of misapplied emerging science. He literally believed in racial supremecy and was trying to build an ethnostate. This motivated him to define groups of ethnic “undesirables” and also to lump in other groups that he found politically inconvenient. Read about the scapegoating of Jews circa that time. He likely believed his cruelty towards them was somehow justified because he laid all of Germany’s problems (economic issues, humiliation of the country and loss of territory post-WWI) at their feet.
TL; DR - Bad actors believe their evil behavior is justified.