The amount of time you spend playing DOOM-type games naturally decreases once you get good at them and you get something out of your system. The DOOM players who tore up their high school had other problems. I was personally creeped out by the school itself, which from the helicopter views actually looked like a DOOM scenario. The rationale for such cavernous, soulless schools is beyond me. They're building one in the town where I live, and I expect it to be shot up one day by a disaffected youth haunted by the daily prisonlike impersonal atmosphere.
Nobody shoots up small private schools where the kids get lots of attention.
It was about a similar instance of disaffection, exacerbated by the vacuous environment of modern suburbia. This problem is not going to go away as long as children are warehoused in a perverse environment where there are too many kids for anyone to know what's really going on. Perhaps these two jokers could have been stopped by their parents or who knows who. And perhaps the school shouldn't be held responsible, although it was the school that was shot to pieces. Whatever the case, the underlying alienation and pent-up hostility are not going away.