This really needs saying, and bravo to Matt Gemmell for saying it.
There are naturally many, many gamers who behave themselves, of course. That’s not in question. There are naturally many, many football (in the British sense) fans who behave themselves too. But their respective entertainments are notorious for appalling misbehaviour on the part of their most zealous proponents.
The existence of an unremarkable majority isn’t an excuse to wash our hands of the actual problem. The gaming industry owns it. The parents who sit downstairs while their teenager is upstairs playing online on his Xbox or PlayStation own it. Everyone else who’s playing owns it.