I'm on the fence on this one. I don't watch a lot of porn, (it doesn't compare with what goes on in my head), but I see both sides to this argument. I have seen a few videos, not sure if they were pornhub or some other site, that clearly cross the line of the law, or at least they seem to in my view. It's my understanding that in Canada--and probably every other western country-it is not only illegal to depict children in sexual situation--which there is a broad consensus on--but also to show actors that appear to be children having sex. That last point is what I think gets ignored, as there do seem to be a shitload of vids suggesting that the participants are kids. I can't believe it would be that difficult for any porn site to keep such stuff from being uploaded, if they really wanted to.
As for the rest of it, I think I'm pretty liberal. Rape, race, and humiliation vids, should be allowed as long as they're in someway marked as drama. Hell, if you brand everything depicting a submissive partner as "abuse" you may as well completely eliminate Japanese porn. In today's society it's almost impossible to discuss or admit, but there's a dark side to what excites people sexually. I have known plenty of women, in fact I'd guess more than half of those I've been with, get off on being controlled and "used". I'm not saying they want to be disrespected, but a lot of women definitely like the chase, the capture and the (mock) subjugation.