The thing about billionaires it that they could just stop. It's not a skin colour, it's not an ethnicity or even a religion.
If they wanted to they could redistribute the wealth. They could use their power to close the political doors they exploit.
Wouldn't even have to check themselves out, wouldn't even have to adopt some monastic lifestyle. But they would rather live in a world where they have lifetimes of obscene luxury at the expense of others. At a certain point you have to ask if causing suffering is part of their fun.