As I've said, even if she had been acting/paid - it is still dangerous. Simply because others could view the video as standard sexual behaviour - where 'no' means 'keep going - I want it really'...
This reminds me a lot of about the argument some people make, "Violent video games breed violent individuals", before they proceed to try and deny everyone access to something they enjoy.
I don't know if there have been any studies into the effect of rape-y videos on men, but as far as games are concerned I go with the view that violent games only affect people who originally had violent tendencies, and I'll apply that argument here. It wouldn't be fair to deny all the innocent by-standers access to their fetishes just because it may be viewed by people who want to do it in real life.
Just to be clear, I don't condone this kind of behavior in real life and would never engage in it. But this video is obviously just 'petite-girl-taking-an-eighteen-inch-cock!!!' porn, and really mild compared to some other real rape porn on the net. Like another user said I think this was just very well acted and it's just pandering to certain people's kinks.
I sometimes get turned on by BDSM, but there's no way in hell I'd do it in real-life for fear of both my and my partner's safety (I know it can be done safely, but I always imagine the worst case scenario and chicken out).
Like-wise some guy's may get turned on by the fantasy of a beautiful woman writhing around on their (imagined) huge cock in a 'hurts-so-good' fashion, but in real life they could/would never inflict such abuse on their partner. So to satisfy that fantasy in a completely harmless fashion, they turn to porn. And the porn industry is always willing to satisfy a paying customer.