I am sure the 60 something shooter was a well-known video gamer.
I don't quite understand the obsession the NRA has with computer games. If there is a link (and no link has been proven as far as I'm aware) it's not the fact that it's a computer game that might encourage someone to go on a killing spree, it's the fact that there are games that replicate using a gun for it's intended purpose under the second amendment - killing people.
This self-appointed militia carries out live fire exercises and practices killing people.
After all, the second amendment says nothing about the right to enjoy recreational shooting, or hunting, or having a wank while you rub the cold hard barrel of your AR-15...