From a very young age we’re basically taught to think of racism and “anything bad” isms as something “very bad people [consciously] do.” We are always taught to identify with the good guys and wonder what the bad guys were thinking. We then have a lot of trouble actually idenifying evil thoughts within ourselves, because we don’t see ourselves as being “evil people.”
But part of truly understanding the horror of many acts in history is understanding that the people who made them happen were not particularly evil- the people that followed weren’t particularly evil. That evil often happens in little steps, tiny jokes and references and cultural nuances until something snaps and the whole thing snowballs into chaos and upheaval. Evil as it occurs when groups of people are denied rights or killed or discriminated against or whatever isn’t necessarily the result of an evil thought, but rather the result of a lack of conscious thoughts fighting evil.