It's not illegal to ask about race, but, asking about race is a good indication you are discriminating based on race, which is illegal. As to why they do it? I

It's not illegal to ask about race, but, asking about race is a good indication you are discriminating based on race, which is illegal. As to why they do it? I'm guessing that they either don't know not to bring up race or they don't care about discriminating based on race because they probably won't have any consequences. I've seen plenty of casual workplace sexism and racism in my life. It happens.