I'm not sure who made the claim, but I read that during the 1970s feminist movement some claimed that all sex was rape. Why did that person think that women could never have consensual sex?

The person most associated with this claim was Andrea Dworkin, though she was not alone in asserting it. The claim was a bit hyperbolic, but reflected an interesting, controversial claim. Consent, she argued, presupposes rough equality. If you are a violent person holding a gun, and ask me politely for all of my money, even if you don't threaten me, my handing it over is nonconsensual. And that is the case, on this view, even if, had you not had the gun, I would have consented, out of generosity, to give you the cash you wanted. The presence of an unequal power relationship, and the background of potential violence renders consent conceptually impossible. Now, Dworkin argued, given the tremendous power disparity between men and women in the culture of the USA in the 1970's and 1980's, and the prevalence of domestic violence with men as actors and women as victims, a man's request for sexual activity is too much like your request for cash with the gun in your hand and a history of violence. ...

What's the moral problem with pornography? As far as I can understand it, it hinges on the concept of 'objectification', which seems to mean treating someone else as a means to your own ends rather than as an end in themselves. But if I go to the corner shop to buy a pint of milk, aren't I treating the guy behind the counter as a means to my own ends (buying a pint of milk) rather than as an end in himself? Does buying milk have the same ethical status as pornography?

But also note that there is a lot of reasonable debate about this, and there are those who defend the moral permissibility of pornography as a form of commercial exchange in which all parties who participate voluntarily benefit. Note also that communities and subcultures vary quite a bit in attitudes towards pornography. One does have to consider the facts at some point: what is the psychological effect of consuming pornography on its consumers; what is the impact of pornography on those who model or act? What is the impact on social values and the treatment of others? There is surprisingly little consensus regarding these data.