If a Human could treat fellow Human beings of differing ethnicity like scum (Note that, no offense, Russia today is a big offender according to Amnesty International and Moscow Bureau of Human Rights), imagine another intelligent sentient species? It's not going to end well for the ponies in the ghetto
There a book published once during the day of the British Empire. It suggested Africans were an inferior or less form of human. This sparked burning controversy, because it suggested Africans were HUMAN!
And my friends wonder why I have nothing but contempt and hatred of the past in general, any time before the 1950s? People get nostalgic of the so called 'Good old days', watching reality with their nostalgic filter; but the truth is, there's NOTHING good about the past. NOTHING AT ALL. But they do, and that's what cause them to cling to old hatreds, old ignorance and old bias.
Only by remembering the past and HATING it, hate it for its flaws, its prejudices, its weaknesses, its injustice, its dissonant values, would we be able to progress forward into a brighter future - a fairer world, a better world.
I read the history books. I never seen anything good other than the parts where Mankind moved 'forward', parts where movements, reform and revolutions brings down inequality, injustice, conflict, persecution and tyranny of that age. Those were the only good parts I ever read. I could be biased, though, as everyone would inevitably be, so there's the benefit of the doubt.
On the side note, you would be interested to know people are lot more casual with the various currently illegal drugs back then then now.