I tend to think Gamergate was a brewing culture war that was just looking for a spark to start the fire. Gamer culture has had a persecution complex for well over a generation, particularly with respect to the press - even the gaming press. Being repeatedly insulted and attacked by the media has made them circle their wagons instinctively. Combined with a substantial fraction of gamers that are
intensely misogynistic and this ugliness was practically inevitable.
The problem is that gamers picked a fight with SJWs, which are effectively their own mirror image - the same obsessiveness and mean-spirited put-downs and in-group high-fives. I mean, the fact that the SJWs are right is almost immaterial - in the words of The Big Lebowski: "You're not wrong, Walter, you're just an asshole". Online social justice groups have a knack for utterly alienating and insulting everyone they could ever hope to convince, even those who broadly agree with them.
Combine that with Gawker media's spectacular ability to stir the pot, and a few prominent right-wing culture-war bloggers feeding the gamer-gaters' persecution complex, and we're seeing outright radicalization.
You isolate and insult a guy and then give him an online culture of like-minded outcasts and they start encouraging each other to do drastic things. There are obvious parallels to other movements of angry young men...
It's a perfect storm, and it's only going to get worse before it gets better since anybody who's trying to talk the gamergaters down from the ledge has to have infinite patience for their monomaniacal rationalizations. They see themselves as the defenders of rationality surrounded by SJWs who fling glib insults... and gaming is founded on endlessly grinding against a pointless task for fun.
It's profoundly sad to see so many gamers rally behind that gamergate banner. To see harassment and threats and ruining women's lives become the public image of core gamer culture.
I'm really worried that this is going to get worse before it gets better. The "us vs. them" mentality of the hardcore gamer world is too old and well-established, and everybody else involved is either feeding into it or is drowned out by the din.