Humans segregate themselves due to kind preference, we are a tribalistic lot. Kind meaning those that share easily identifiable characteristics. That’s why you live in a more or less homogeneous community where the dominant ethnicity is shared by you. My ancestors were slaves during the Roman times yet I don’t hate Italians, perhaps there is a cutoff of hating people you don’t know because other people you don’t know oppressed distant ancestors who you also didn’t know, what is that cutoff? IS it 150 years, 400 years? What about the ancestors of those killed fighting against slavery? Are they to be disliked as well because other people from long ago owned slaves?