Well, I'm a person of colour, but if an SP has an issue in doing business with me because of my ethnicity, better I know about it up front on the phone rather than getting all the way there and then having an issue. As an earlier post said, the services provided are very intimate no matter that it's for cash and there can be various reasons (racism, age, recognition within a specific community, etc) that would circumscribe who an SP chooses to work with.
Why waste time with whether this specific SP is racist or not? There's plenty of other choice out there.