But nothing is stopping a black person from seeing the ad.
In FB's case, it's like posting an ad at a med school (any, med school, regardless of demographics) and say...you can only view this add if you're white.
When I was in college, lots of recruiters advertise and sponsor with the Society of Black Engineers...of Society of Women Engineers. Nothing stopped me from going to those meetings, and I did attend some. Their meetings were advertised to everyone. You weren't prevented from going to the meeting and listening to the recruiters.
Was I offended...yes and no, but more on the no side because I had the same opportunity as everyone else at school. I'll tell when I was offended. I went to a career fair one semester I saw Microsoft booth that advertised scholarships for minorities (or maybe internships? I don't know, I hope not because that woulda been illegal, in hindsight!).
There was a young Indian woman staffing the booth and I asked if I could apply. She said no...looking for blacks and hispanics. I'm Asian...so was she. Microsoft shoulda sent a black/hispanic engineer to send their message across better, too.
Let’s just say when they walk the neighborhood and I open the door, they are flummoxed when they don’t feel comfortable using their usually spiel...