It depends. Is it because they don't want to be in an unfamiliar environment, or because they don't want an unfamiliar environment to be around them?
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).
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).