Johnfarleysruskin - I am pretty impressed that you've made such clear points and have such a good argument. Forgive me, but I have been one of those assuming that most men are pro-porn, and having seen this thread I am not so sure anymore.
I can see how, as with any socially acceptable norm, porn is rated as something that the open minded partake in if it tickles their fancy.
I've always been uncomfortable with the portrayal of both sexes in porn because I can see the actors are damaged people. It is sad to see them glorify a lifestyle that promotes any act nobody would like to commit - or have done to them - in real life, but somehow get off on.
It's true porn is like a drug, the more you get the less it satisfies, so you need to take it to the next level. I believe that is why there is a higher demand and tolerance for more extreme and unpleasant stuff.
I was shocked by the Knox link. I feel sorry for that girl who comes across silly and giggly and very naive, and equally sorry for her parents if they ever get to see what their daughter has subjected herself to.
I've been in relationships where my partner has claimed the homemade stuff is ethical because it's for exhibitionists who wouldn't do it if they didn't get a rise from the experience. But now I'm not so sure if even that is true. It seems that even the most seemingly innocent(!) home made porn could be forced.
As a mother of son's I am concerned about what I will teach them in regard to porn and how it is not normal representation of either people's bodies or of the sex act. I would hate to think porn would be their teacher 
So, once again, thanks and especially to those males who have given me a new hope that you're not all tarred with the same brush!