I see your point. I think it wasn't the best counter.
You made me realize that its actually certain things that we as a society decide as sacrosanct and not grounds for prejudice. So it can be with race, which involves no choice, but also religion, which does involve choice. Or political affiliation, which also does involve choice.
The only thing that really matters is people's ability to make decisions. Their religious and political views can very easily reflect a failure to make good decisions, and that has a real social cost. Race is nothing like that. Neither is most physical disability, sexual orientation, nor suitably passive statements about political matters or religious affiliation. That's why those things are protected.
You made me realize that its actually certain things that we as a society decide as sacrosanct and not grounds for prejudice. So it can be with race, which involves no choice, but also religion, which does involve choice. Or political affiliation, which also does involve choice.