Note and apology regarding previous post: I previously posted mass shootings as being a combination of crappy gun laws and mental illness, as an example of not focusing on a single factor for some atrocity (or anything else). As it transpires, people with mental illnesses have a lower propensity to be a mass shooter than the general population (partly because they don't have as ready access to guns, but probably other reasons too). The main motivation tends to be a combination of rage and humiliation. It doesn't necessarily have to be personal humiliation, but examples of humiliation providing impetus to some social movement or another are all over history.
A decent number of my friends (peaceniks, homosexual emancipators, free speech advocates, pro-west etc.) really don't like Vladimir Putin. They even go so far as to suggest that it seems really weird that he got voted in, particularly democracy advocates (who seem to be very shortsighted). But people don't necessarily vote for the most progressive or the candidate that benefits themselves. In Putin's case, he ran for presidency at a time when Russia was a punchline for alcoholism and grotesque mismanagement. This, after the collapse of the Union and the rise of the Oligarchs, was an extremely attractive option to many Russians. He promised, in part, to redress the balance.
It is believable enough that to be feared is better than to be ridiculed.
Humiliation may not be the most powerful emotional motivator, but it is perhaps one of the easiest to ply. For the leaders of a social movement, the ability to manipulate humiliation is tremendously important to the survival of that movement.
It does seem sleazy. Trolling, in the internet (and sometimes in real life), can be considered the art of humiliation. It is sometimes motivated by some higher cause, but is rarely used in such a way that strengthens the cause that it is motivated by. It is mostly for fun, to revel in ones own smug superiority at the expense of someone else's pride (or whatever). It certainly was for me. I had heard trolls justify trolling by saying that it was to make people aware of their faults. In the context of social movements and assuming that statement at face value, it is remarkably poor at it. Humiliated people get defensive.
Of course, we'd like people to respond rationally and be civilised and all that. But that's a far cry from specifically poking someone's numbers and blaming them for their outburst (especially on a large scale). It certainly doesn't affect social change as effectively as convincing a crowd that your target is responsible for their humiliation.
Elliot Rogers (oh boy!) has been discussed a significant amount on the internet. He is one of the internet's own (or was). He was a narcissist or a sociopath, certainly, but he borrowed the 'redpill' rhetoric, and as such drew the ire of Social Justice groups who blamed his actions on 'The Patriarchy'. Nonetheless, you can see the effects of humiliation. Even in a small way, most people (if not all) can understand that gut wrenching defensiveness you feel, and how it amplifies past grievances into burning embers that sit at the back of your throat. And this easily fuels rage.
This does not make that party wrong, contrary the troll's thesis. However, it does make them extremely vulnerable to manipulation.
This does not also justify his actions. But understanding his reasons, without condoning, is important to controlling others like him and to prevent more. To simply say "he shouldn't have done that" is about as "right" as saying that one should just ban crime. Neither does this shift moral responsibility. But this isn't about that.
Germany after The Great War was humiliated in its defeat, and that national sense of shame in part led to the rise of Hitler and the Nazi's. Of course, there was also the economic disaster of reparations, and the volatility of ideological parties vying for control in many countries. Again, it plays its part.
Humiliation is not the only motivating factor for social movements. But it is a powerful one, and one that skillful organisation should use to improve recruitment and retention.