It's an unfortunate occurance. But when the population begins to change like this, property values go down. Sad but true. Basically you have to get out before you loose everything you invested in your home. It happened to me in a very short time.
Sorry to hear your story. The very opposite happened to me.
I moved into a neighborhood where hookers came to the door!
Nevertheless, what you say has alot of validity. People want to live in an area surrounded by people "like themselves."
Of course, knowing the area like I do, white folks would really look stupid if they start driving 40 miles to go to work just to get away from "those people."