Too large an article to read whilst at work but I wonder if this is being portrayed as a race related split or whether it is just an attempt to build a more pleasant place to live in. That the poverty and race connection is a distraction. Since the new city is apparently likely to be 30% of folk who consider themselves black, then I suspect it is wealth making an ability to move somewhere better.
America is, after all, predominantly made from immigrants so a mix of race/culture should be something they are used to. And it is also predominantly a place where one is expected to look after their own interests, which is what these folk are planning on doing ?
Tackling the lack of spreading the wealth around so all feel they have a decent stake in their society, is a different issue but one that ought not be ignored.