Unrelated to the older post...
While this trope is probably not very suitable to apply to real life, there is one thing that comes to my mind:
After school shootings, the perpetrators tend to get popularized as this, particularly in the cases where the perpetrator committed suicide at the end. Everyone thinks of these guys as poor butt monkeys who have been bullied by their classmates for years, treated unfairly by their teachers and also treated badly by their parents. While this may be accurate in a few cases, most later rampage runners don't have a life that miserable. (Some of those with not-too-bad lives may still feel like the poorest thing on earth, though.) There seems to be other motives involved in most cases instead of, or in addition to, a desire for revenge.
So because it is not a very accurate description of real-life mass murderers, in which category would it go? Memetic mutation?
Also, of course the phenomenon of describing school shooters as Woobie, Destroyer of Worlds is an attempt to find a Freudian Excuse for the perpetrator.