It's not racist IMHO for a prossie to advertise and say she doesn't see certain people because of bad experiences, or for no reason at all. If it was a knock-shop that would be different, but we all have a bottom line in who we are prepared to shag and it might not be logical.
A white European trying to get a shag with a genuine Japanese prossie in Tokyo is up against it too. Japan is an isolated country, both geographically and culturally. They are generally paranoid at heart about non-Japanese people. If you tried to force a prossie to service you by claiming she was racist if she didn't, and she was scared, however unreasonably, you could maybe say she shouldn't be in that line of work but it would still be unethical to insist or pressure her. Some people are fucked up, and that includes prossies. In fact we are hardly surprised that there are more fucked up people who are prossies than in the general population. It's sad, but true.
So imagine in an enlightened world where prossiedom was an accepted and regulated profession, and women could become Firefly
certified, then of course such problems would either not exist or be hardly noticeable. Until then, we are born with the shit we inherited for better or worse. If one prossie refuses to shag you, find another one. There are prossis of all shapes, sizes, looks and ethnicities that take all-comers.