I think the issue here is the possibility of digital red-lining. While recognizing race is not racist, treating people differently because of their race is racist.
I don't think targeting based on race is wrong, per se. BET shouldn't be forced to advertise to white people, a Christian dating site should be allowed to target Christians, etc. But housing is another category altogether and ad targeting based on protected categories should be disallowed. It sounds like Facebook realizes this and called this a "technical error."
There is that history, and now those laws, for housing discrimination. Despite those laws, housing discrimination continues to exist. Enforcing those laws is a bare minimum.
Insofar as the spray-tan vendor constitutes a public accommodation, this is untrue. But those laws have different precise contours than those for housing and employment, and would not seem as likely to apply to ad targeting.