I heard an anthropologist talk about how humans perceive one another.
Generally speaking, we tend to see those who are familiar to us as "the same" while those who are unfamiliar as "different"
When I was a child, I remember not fully realizing that my grandparents had an Irish brogue. That's just how they talked. But when my grandmother's nephew was around, I could barely understand him.
That's what happens to people.
We "hate" based on people we haven't met, based on unvalidated beliefs about a stranger.
We are unable to truly see each other until we get to know each other.