Dude wrting this article, let me give you some examples:
1. In Skyrim you can sacrifice a best friend (follower) for a Daedra named Boethiah in order to get some piece of armor
2. In Skyrim you can sacrifice a priest in order to become a canibal for another Daedra
3. In all GTA games players go on killing sprees against police, civilians, anything that moves.
4. Niko, a guy who wants to escape crime, kills so many people in GTA IV in missions in order to advance the plot and he's doing it for MONEY, ONLY MONEY, sure he needs it to get a better life and pay his cousin's gambling problems, but it's still for dirty money.
5. I don't need a 5
6. I don't need a 6
7. Do I need to go on?
Killing the guy via phone in that Michael Mission (I don't have xbox, I saw the mission on youtube) is nothing. It's just murder for the sake of revenge. Michael is genuinely moved by what just happened, he didn't expect a hacker to be so violent and actually plant a bomb in that thing. Michael is reckless, but not the culprit in this case, he was a tool, yes, but these things can happen in real life also, people being used for something they don't want to be a part of, so GTA V didn't go overboard with it.
The game is not sick or overly violent, it's what it is. If anything, we as gamers are sick for playing games like GTA III, VC, San Andreas, IV, V. Simulating the life of a criminal is just that, Rockstar did a masterful job, the moral is that in GTA V a white guy is rich and miserable, so money by itself doesn't bring happiness, crime doesn't pay and all that, his wife's cheating on him, his son doesn't respect him and is insecure about himself cause Michael failed as a father and role model, and so on. Michael is a victim from the first cutscene of the game. Is the victim of his own way of doing things, falling into a life of crime, and somewhat enjoying it. Franklin is what Michael was in his youth, a poor kid, wanting a better life (only difference is his black) and Michael relates to him, and as for Trevor, yes he is a maniac, and no I don't know his story yet, but if I'm correct, GTA V will offer narrative and a perspective on why Trevor is the way he is: been in the army, and all that. The chemistry in the game, from what I've seen is great, the morality is ambiguous, the characters are flawed, not loveable, but identifiable, I'm pretty sure everyone on this forum has a bad side to his personality, don't lie. The characters in GTA V are cynical, and I'm pretty sure this is why most find a hard time liking them.
PS: You mentioned "terrorist act" a few times. In all GTA games you commited terorist acts, either by plot or just player faffing about.