https://www.apa.org/science/about/psa/2003/10/anderson
As well just because someone fit's a profile does not mean they are predisposed to commit acts of violence. That being said, when there is a pattern, there is a pattern. There are many young white males, of similar experience who do not pick up a gun and start killing people. That being said, there is a definitive pattern of behavior and interest among these white males that do, rejection, isolation and immersion in video games (almost always violent) are certainly some of those patterns.
Also please stop trying to pin it on alt-right (or left for that matter), these guys are popping up all over the political spectrum.