If he really wanted to make an impact he'd ask gamers as a community of people to show support by each donating what they can (from a dollar up?) and giving that to the families of the victims. This would have a tangible result as well as avoid making a statement on the issue of violence in the media. As someone who runs a website he could have set up the donations through his website and provided them with some relief.
The modern relief, money - pour enough of it and aaaall problems will go away.
Want to -really- do something good?
If youre in school, go to talk that loner student who is always chosen as last in sports class. If youre at work, go eat lunch with that college you sits next to you, but whose name you can barely remember. Do you ride the bus? -offer your seat to the old lady. Stuck in traffic jam? Dont even think about shouting other drivers, even if they dont know how to drive - change the radio channel to some chill channel and dont stress about something you cannot affect.
World is not going to be destroyed by some Mayan calender, Nostradamus prophecy, Niburu falling from sky or even the newest CoD 666 - its going to be destroyed because we fucking forgot how to smile to strangers and say thank you & youre welcome.