Speaking as a WG, I don't have problems so to say with any race (I've shagged people who are black, white, Asian oriental, Jewish, etc, in my civvie life), but I do take care with my working life. Not so much about race, every single individual who has fucked me with pay has been white, but majority of the population is white. Problems with boundary pushing from more than a few asians, only a couple of whites. Trying to yank condoms off, mostly whites and a few Asians. Never had a single problem with someone who is black or oriental. So I chat with all on the phone first, anyone who seems not quite right (won't say what they want services wise, even to the point of won't say if they want GFE/kinky/PSE or other, is very cagey when asked questions, has "no preferences" on styling) I steer clear of. If they don't know what they like, how the fuck am I supposed to know?
Honestly I wish I had more black clients, but then that is where my personal attraction preference lies. But a good dick is a good dick.