Of course, white society is perfectly homogeneous and not diverse at all. Especially if you're in prestigous, guilt-mongering colleges and newsrooms.
I'm here in the Bay Area. What's going on is that middle class blacks are leaving places like Oakland, San Francisco and Richmond to get away from crime, drugs, gangs, etc. They don't want their kids exposed to this dysfunction, so they are moving to the exurbs like everyone else. Actually, for once, this is not a racial issue, although the Chronicle tries to make it one.
I live in the East Bay, in a racially mixed city with an average income of nearly $100k a year. Many people here have escaped from the big cities and are great neighbors.
It's not color - it's culture.