Robbery is how they finance themselves, but the self-esteem part is VERY true. The lefties don't like this part, but good research has shown that the thing leading to this violence is not LOW self-esteem, but when someone's self-esteem is threatened. In other words, if we prop it up artificially, it is more likely to be threatened, leading violent reactions to try to preserve the false self-image.
Ridiculous. What leads them to do the act is that they make a snap decision that they will succeed. Barring the psychotic killers, all of those research subjects would back down if their victim posed a risk after their initial judgement that they didn't. Otherwise gitmo would be empty and courts would have no defendants to try.
These creeps size up their victim and go. They don't attack what they can't handle and they don't proceed against what proves to be a clear threat. In a good number of cases they kill the victim regardless, because they pose a risk if left alive.