I'm linking despair to mass shootings, which includes massive debt which will be next to impossible for the person to ever dig out of.
I could somewhat see that. . . but much of what these people complain about in their rantings before this happens isn't student debt or something economic. It's often social.
You are often talking about people who are anti-social or at the very least strongly lacking in any social skills and just have a terrible time of forming solid relationships with anyone outside of perhaps their parents.
You don't hear. . . I can't get a job and I owe a ton of money. You hear "people don't want to be around me, be friends with me, girls don't want to date me." And in this frame of mind people turn this sort of thing into the fault of other people in which they generally take out these social frustrations on others.
Part of me wonders if the internet hasn't created an environment which creates more anti-social people? It could also help foster anger among people like this. . .
I could see how having anti-social people congregating together could build up anger at more social people who have lives in which a few of them might turn into violent action.