Morality is relative. There are few other media that show this better than games. The reason being that "computer games" [which for the purposes of this we'll assume encompass all digital interactive things] allow for meaningful choice.
Players/users decide who to kills/what to destroy; these decisions are informed by which would be the most rewarding based on the rules of the game their playing.
In his article, Miguel Sicart references Grand Theft Auto III. [Why is GTA always the focus when talks of ethics and morality arise? I mean Mario has been murdering turtles and goombas for decades]. Grand Theft Auto is an interesting case. Though it gives on the freedom to commit wanton acts of violence and corruption, it adheres to societal morality sensibilities. Hurt people and destroy things for long enough and you will be made to deal with the law. While initially intended to be a hindrance and deterrent from too much mayhem, something else happened.
From even the first Grand Theft Auto, breaking the law became a game within a game.
Stepping outside the bounds of morality and seeing how much awfulness you could enact before being cause was fun. The player wan't rewarded for the behavior but the repercussions weren't enough to deter people from wrecking havoc.
So, while the game and developers do their best to replicate/reinforce real life standards of ethics/morality they fail because of players.
It's no surprise, really.