Author here. Thanks for your comments.
The reaction to Newtown hit me particularly hard, as the victims were little children, and my wife was 7 months pregnant with our first child at the time; every mass shooting has bothered us, but this one struck us in particular if only because we were about to become parents ourselves. And, also (as the piece says), it happened right when I was starting to get frustrated with Far Cry 3 (and, in particular, with what FC3 was attempting...
I mention games specifically because it's not a passive media; you actively participate in it. You watch movies and read books and you listen to music but the game only performs if you physically engage with it. And I mention games specifically because *most* games - not all, of course, but most - involve shooting something in order to progress. Shooters are, by their very definition, violent - but should an adventure game like Uncharted require you to kill 700 people?