Taken over time and populations, these very slight differences in preference (and, realistically, in the USA, it is unlikely to be "slight") lead to segregated neighborhoods.
If anybody has the original, I'd love to see it again and find out what I've mis-remembered. I couldn't find it.
I think I can make a fairly strong argument for homosexuals preferring to live among themselves as being ultimately detrimental to society (reduced exposure to homosexuals allows intolerance and misunderstanding to fester), however I would never dream of calling the desire to isolate themselves from hatred "wrong".
Edit: I take it from the downvotes that we're just talking about segregation across "'skin color' / 'irrelevant heritage'" lines for some reason...
There's a good chance that atheists who choose to live only among atheists are going to suffer worse outcomes. Living in a diverse society leads to more perspective and better ideas, and an eventually better society.
Only living with other gay people or other Hacidic Jews or other white supremacists may feel comfortable, and it might lead to a functioning society. But is it ideal? Does it leave the people better off? Society at large?
I don't actually know the answer tho these questions, but I suspect you're better off meeting all sorts of people, living in all sorts of places, and absorbing all sorts of ideas.
I don't really believe in right and wrong.
I think we pretty much agree in other words ;)
If they're hostile to other groups in some way, that's not a good thing (I don't want white/black/pink/red/... people around my house). But there's nothing wrong with staying in some area because you want to be close to your family (which leads to "natural" race concentration within that area).
Thus communication problem directly impact the frustration of each party about others. Then more violence will occurs.
To be more precise. Yes, everybody want to live with people which share the same values. But this local optimization have a bad effect on the society viewed in its totality.
Taking my own example, I believe that not being segregated in school had made me lose some hours of good Math. But I believe this experience made me more tolerant. And it is also certainly true for the others.
There is no perfect society model, but my inclination is to believe that more communication is never a waste and that any lack of communication is potentially dangerous.