Game would not have helped this man. I don't think anything would have.
Game can help a lot of people. The fat guy who needs motivation to hit the gym. The nice guy who can't understand why he keeps getting turned down. The kid with mild Aspberger's who never took the time to think about how he was coming across to girls. If you're that kind of person, a copy of Day Bang and a weekend spent reading Roissy can make a huge difference in your life.
But this guy? He's something else. I'll link the video that vannigoc found, because it's unbelievably instructive.
If this guy was auditioning for the role of a serial killer in a Hollywood movie, he'd beat out every other actor on the planet. Roosh used the word "creepy" above, and while that's the same word that first came to my mind, I think a better one is "terrifying." Look at the weird tics as he moves. Listen to the way his voice is so soft, and yet so angry at the same time. It feels like he could break into a screaming yell at any second. The strange pauses in his speech. The bizarre, obsessive way he talks about women around him and their, "revealing shorts" and "cascading blonde hair."
Then there's the way he justifies himself, with lines like, "I am the perfect gentleman," and "I drive a nicer car than 90% of the people around here."
No wonder women ran away from him. I would. Bizarrely, it's possible that the fact that he snapped in such an obvious way and was caught so quickly is a saving grace: I could easily see this guy kidnapping women and torturing them in his basement, going undetected for years.
I am not a fan of western women, and I'm certainly not a fan of PUAHate. But I don't think either of them can be blamed for this. This man was broken, and he was broken in a way that I don't think anyone or anything could fix. If it wasn't women it would've been something else. Even something as simple as a lost job would've been enough to send him over the edge. There are no lessons to be learned here, except that there are evil, evil people in this world.