There's tons of conflict between incompatible cultures, but we don't resolve them by ignoring them. Cultures that intermingle more, humanize each other more. Humanizing misunderstood people and cultures is how we got awesome stuff like suffrage for all (voting rights) and marriage equality. Nothing humanizes someone more than going over there and just talking to them like an ordinary human being.

I think it's arguably natural, in a tribalist way, to stick together, but that doesn't necessarily mean it's better