I think what a lot of people don't realize is that a lot video games don't allow you to act violently without repercussion. Usually you're fighting someone who is "bad", or if you're attacking "good" people there is some kind of consequence, even if minute.
Take GTA for example. Sure you can run over people with your cars, beat up hookers and steal their money, and generally public enemy #1, but the cops STILL come after you. Even if it is absurdly easy to lose them, it's still implicitly telling you it's wrong and there are consequences for doing it.
Obviously this isn't a catch all statement, but it's definitely something people don't consider when judging how "impactful" the game can have on someone psyche.