You make a good point and I thought the same thing after I made my initial comments. Another one I thought about was what if a person truly strongly believed in segregation, even maybe it being a part of their religion. Does that mean it’s ok for them to deny black people? That makes me deeply uncomfortable to put it lightly; I don’t think that is justifiable.
At the same time, there is something very personal about creative pursuits. Graphic artists can reject any idea and they don’t have to justify it. And this is something that is custom made for each customer. If the artist isn’t interested, and even is morally opposed to performing the work, even if they were legally required to do it, is it going to be their best work? Can they be penalized for deliberately doing a terrible job? I don’t know