Well, I guess it wasn't my last post as Irock has brought up a topic that I haven't addressed and which I should. I also moved the topic to ED, but maybe a better solution would be to split the news parts and the debate parts.
To your first question, I think it is a matter of common sense that how much respect you have for a person is inversely proportional to how much you want to brutally rape them and deprive them of their humanity. As a corollary, the amount of respect you have for a group of people is inversely proportional to how much you want to deprive members of that group of their humanity for attributes deriving from their membership in that group. Moreover, it is a fact that discrimination exists. As discrimination is not inherent, there must be aspects of our culture which contribute to it. I think those factors, taken together, are enough to suggest that rape porn contributes to the dehumanization of women in our culture (nonetheless accepting that not all rape pornography is directed toward women).
It is practically impossible to create a controlled study with respect to why humans behave in the way they do. There will always be variables that we cannot account for that could influence the behaviours witnessed. For instance, it is impossible to really "prove" that punishment deters future crime. We simply deduce, as a matter of common sense, that a reasonable person is less likely to choose to act in a certain way if he or she thinks they will be punished for it. In my opinion, common sense is reason enough, especially when the behaviour in question (easy access to visual aids for masturbation) has very little social value and the conceivable harm (hatred and discrimination) is very serious. And again, this isn't criminalizing possession, just production and distribution.
The question of medium is more contentious. I think the medium of video games and the medium of pornography are different enough that there is little merit in analogizing them. The pleasure derived from video games is usually a combination of participatory description, creation, and skill. They tell a story, they allow you to create something, or they are skillful contests. MGS4, for instance, is heavily story-based - the actions you take in it are intended to unravel a pretty linear story - the pleasure in that video game derives from participatory description. Other games like the Sims, are practically all creative. Smash Brothers is more or less entirely skill-based. Most games combine all three elements, like GTA. The story parts of the game are more or less participatory description, while the freeform elements are about creating your character. The joy you get from killing innocent people is not so much from imagining yourself killing innocent people as it is from creating a character who does these things. Or, alternatively, people can derive joy from video games in the skillful elements of it - so, you could go on a rampage just to see how many innocent people you can kill before the cops kill you or arrest you or whatever, and in that sense it is about skill. Some people may in fact derive the pleasure from imagining themselves doing it, but there is nothing in the medium of video games that necessitates or assumes that.
The joy derived from pornography, however, is all about immersion - imagining yourself in the scenario. There is no real story, no skill, and no creativity. Deriving pleasure from watching rape pornography is all about imagining raping someone (or imagining being raped). That is why it exists, and that is the only reason it exists. It is not the same as a video game. That said, there could conceivably be a video game where the purpose of it is to imagine yourself stalking and raping someone without any story, creativity, or skill required. In that case, it would simply be rape porn masquerading as a video game however.
I say all this without any love for GTA - I simply legitimately feel that the purposes of video games differs quite substantially from the purposes of pornography. It's cannot be reduced to: both are about entertainment therefore they are the same. I don't know though; this is a necessarily subjective topic. I am simply generalizing from the types of fun I have when playing video games and assuming it is more or less the same universally. Maybe to some of you, video games are equivalent to porn, reading a book or watching a movie and there is no difference between the ways you interact with those mediums. But I think the differences are quite substantial and that you can legitimately draw a difference between rape or murder in the context of a story and rape or murder in an immersory context.
And just to ensure there are no hard feelings, I do think you are all very smart people and that your arguments are meritorious and influenced by important values. I am just in disagreement as to how they should be applied in this situation.