The shooters tend to be suffering from mental/trans issues a lot of the time - trans more recently. I guess they go hand in hand.
We know mkultra and such was used to fuck with people's heads, who knows what the real driving factors are but I find it suspicious.
Bigger events like The Boston bombing were obviously planned, and a lot of the shootings have so many wtf aspects to them.
Everyone has a manifesto, it's like they all follow the same playbook. It just doesn't seem organic.
Saying that, the US is the only country I've been to where I encountered mentally unstable people in the streets, east and west coast.