It was not great to watch, but it was great to let my parents know who exactly they should stop associating with.
They do. But it's not a law of nature; it's a conscious decision, by people who should know better, to start lowballing real estate and salaries when they notice "too many" lower-income or black (of any income level, including high) people around.
You don't want to call it a concerted effort, but then you look up, say, the distribution of Whole Foods stores in the National Capital Region, and start to wonder.