Interesting thoughts, although it'd have been nice to have more research in the article.
I think games, since they are really not real life, tend to have little or no prohibitive reaction to anything bad done in them - the most that is lost is a life, or the end of the game (so you reload and try again), or a bit less cash, or some guards rush in, who you then kill. For instance, stealing in Oblivion you can be thrown in jail for a while - by omnipresent guards - but you can bribe your way out of it. Grand Theft Auto, arrest means the loss of your weapons, and nothing much more (a larger penalty later in the game of course). Being utterly evil in front of saintly NPC's never gets much more then a sideglance and of-hand comment on how bad the thing you did was, no stand is really taken.
Of course, it is because they are entertainment, and so most of the evil is, even when it is "real evil", not something that is impossible to do - you never have the game instantly end if a law person arrests you in a game (usually, you can just kill the law person and run away scott free) - it is entertainment to become the evillest thing you can, and sometimes the game actively enforces it in the story or missions where all you can do is criminal acts (quite a few RPG's do this with "thief" quests), although there isn't much a feeling of doing wrong, especially when the designers give you no other option!
And I sometimes wonder if the good options are really that nice either. Action games usually give no option to let anyone surrender, RPG games regularly have you killing off wild animals who would likely rather be left alone, and usually absolutely no option is made to arrest or imprison another NPC who has done wrong - perhaps even the same wrong which the player themselves would get arrested for. Makes evil part of the game, if everyone does it and gets away with it too!
I think the Escapist would know that people do play the games to escape (hohoho), be someone else most of the time, fill the boots, be in another world. I think morality, like the setting, the mechanics and suchlike can be up to the player how it goes (or what they choose to play and do) - and its not a bad thing to play the evil side (and like above, sometimes it is funny, and the article states some play it anyway to get all the content too), and certainly most people would not do those actions unless forced in real life.
The multiplayer angle is interesting. If killing or looting does break some form of law, or make the victim worse off, it is problematic - but some see it as pure mechanics or mathematics I guess, and others just like to annoy people, and others do like to do bad things, but that's fair enough, some people are mean and bad - better then them doing it to people in person.