I think people are missing the OP's point.
What people fail to realise is how a lot of things simultaneously influence and reflect societal values and culture.
He gave an extreme example, in that he went on a site about submissive females and violent sex. However porn DOES most often portray women as sexual objects who are there as sex toys for men. I mean some women like this, and so if this is kept to the bedroom on its own then that's fine. However the op is saying that it may not simply be kept to the bedroom, which I think there may be a lot of evidence in favour of this idea. Women are often objectified in real life in the same way as they are in porn. Therefore, op is not saying that the porn causes people to be objectified, but rather this objectification has become our view of women and sex. This objectification leads back to the idea that men have to be alpha and powerful to be a real man. This is what society believes to be the 'norm', but actually it is a norm that is constructed by society these days and leads to all sorts of polarisation of women and men's roles in society. Women are submissive and less powerful. Men as dominant and powerful. This basically causes a lot of the gender issues we see for both males and females these days and porn is a good reflection of these deep desires.