I think that S&M in real life and on the internet are not always the same thing. Some responsible S&M sites make sure to end the scene with the abusee smiling and clearly happy with having been in the scene, but internet porn vicarious fantasy. Some viewers want their abuse abusive. Zombie Girl once told me that one of her billers was demanding that she show the girls on her pants wetting/desperation site smiling and enjoying themselves, but that would be ridiculous as who enjoys accidentally peeing their pants in public. The viewers demand realism, and her models generally found the scenes to be easy work, so she stuck to her guns.
I guess the whole point is that some viewers looking for S&M may be looking for S&M, others searching for abuse may be looking for realistic abuse. They don't care how well the models are treated, they just don't want that interjected into their fantasy. I think that porn surfers are more honest in what they watch than what they do in much of the rest of their lives. I think that people in powerless positions tend to look for someone to look down on or degrade. It seems that in the South way back when the poor white people felt better about themselves because they could look down on the poorer black people. In India they have racially/religiously motivated riots every so many years in which ordinary people commit terrifying atrocities against others. In the middle east you can go buy videos where terrorists behead people. When you're in internet porn you're giving people a consequence free environment, and as a consequence you're dealing with the way people are deep down, and not all people are as pretty as they appear on the surface. Some people want to see rape porn when they're alone on the internet; I, on the other hand, read web comics.

As for race, I didn't realize that so much thought went into it. Has anyone sued over discrimination? I've never sued over the fact that all my credit card offers that come in Spanish have much worse terms than the ones in English.