I've commented about this elsewhere, but the experiences, beliefs and opinions that radicalize ad hoc shooters typically are very removed from their choice of target. Though, heck, he might have written or recorded a manifesto somewhere. Otherwise he was sick and tired of living a life that sucks and just wanted to express pure rage.

Political operatives look for guys like this to turn into assassins and terrorists. Militant groups of the transnational white power movement looke for guys like this at earlier stages for recruits for counterprotests, harassing marginalized groups and liberal voters and other violence to serve their cause.