Yeah there is a big big difference between self segregation for community or cultural or even safety reasons versus forced segregation by society. The former can be fine and good depending on context and the latter is probably never good.

There's a book on the topic, I think it's called "Why are all the black kids sitting together in the cafeteria". Admittedly I have not read it myself (yet, it's on my list and bookshelf!) but have been told by a few that it's a great book on exactly this topic.