The article isn't entirely correct. Following the logic of the newspaper header, it should say, " 'I'LL DO A GRAND THEFT AUTO STYLE MASSACRE' GUN SAYS", and the article should continue along the following lines:
"Tragedy struck when a gun of known description began firing at crewmen on-board a submarine" etcetera.
It's not the gun that kills people, it's not the beer that causes car accidents, and it's not video games that go about performing heinous acts of violence. Instead, it's respectively, "people with mental disorders," "stupid people", and "stupid people with mental disorders."
It's just terrible that it takes tragic events such as these to garner peoples attention. But then again humans are rather silly creatures prone to do the silliest of things, such as voice their opinion through medium of text on an internet forum populated by individuals of whom many are directly connected with the forum's very name.