When men lack respect for women, or treat women badly in bed, it isn't the fault of the porn-- it's the fault of the man. I'm not saying porn has no effect on men. I think it could expose them to a wider range of sexual activity, make them more tolerant of kinks, and yes, possibly even lead them to think some behaviors and attitudes are more common than they actually are. But when things go wrong, even if porn does have an influence, the problem is not the porn itself. It is the person, and how the person relates to their influences. People need to be able to treat all others as individuals-- and realize that you can't blame one influence for the result.
I think that porn, overall, can be a valuable thing-- it allows people to experience their kinks on their own, it enhances masturbation (which is valuable for those who can't get sex partners, as well as those in long distance relationships), and it allows them to have a sexual experience without a partner.
But so many people seem to think that watching porn is responsible for sexual attitudes. I'm not going to deny that it has some influence. But really, watching a video cannot be blamed for a romantic partner becoming less intimate with you, or treating you negatively, or.... some other issue.
It all comes down, as far as I'm concerned, to the lack of communication, and a lack of involvement. If your partner is asking for new things, or things you consider strange-- ask why! If your partner is treating you with less respect-- talk about it! It your partner seems unsatisfied with your sex life-- talk about it. I guarantee that adding a healthy does of communication will do more to fix relationships--and attitudes towards sexuality and women-- than eliminating porn would.