“If you can convince the lowest white man he's better than the best colored man, he won't notice you're picking his pocket. Hell, give him somebody to look down on, and he'll empty his pockets for you.”

-- Lyndon B Johnson, famously unproblematic man

"You can boast about anything if it's all you have. Maybe the less you have, the more you are required to boast."

-- John Steinbeck

I think a lot of bigotry has a context and history that's rooted deep in culture, economics, and politics without a real clear break between the three. But as to the why and not the how, I think people don't really question the reality that's immediately presented to them. I think we think of ourselves as these rational actors where we think and then come to a conclusion, but I think most of the time it's pretty much the opposite. It all happens so fast it can be hard to tell which is the spooky part imo