Didn't read more than the first few posts. I'm in a 4chan poster sorta mood.
Study after study have been conducted on the subject of violence in video games, and not a one has concluded that violent games predispose individuals to exhibit violent behavior. This part of the argument is over. Its not a fucking issue.
Now, the morality or value torture scenes and the like is still debatable. I haven't played this part of GTA 5 yet, so I can't comment too specifically without missing the mark, but generally speaking I think that it all really depends on how the violence or torture is depicted, and what is being implied. If the game tries to defend the use of torture by, say, having you get the information needed to save the day from evil terrorists, its wrong. That's a nono, imo. I don't want media floating around that says I can throw my morality out the window because I or others are afraid of getting hurt or, Hell, even killed.
From what I gather, GTA's torture isn't just wildly inappropriate entertainment or grossly inappropriate in its message. It seems to be disgusting and unsettling, rather than glibly fun. It can probably be interpreted to have something meaningful to say about violence in the criminal world, and, players willingness to just play along and indulge in that sort of violence--to an extent. But then torture gets involved and suddenly the violence is unsettling...