Another form of racial steering, maybe? I can't imagine taking into that into consideration when buying a house. The two times I've purchased a home, I had no idea who the owners were. The second time I knew after a little negotiation, but only because he was being a jerk about something (he was white).

I still have no idea who owned the first house I bought. But I don't question the veracity of your observations. I am just wondering if the process is driven by real estate agents, hence yet more racial steering, of a kind.