and that the political narrative he gave to his actions was superficial, yes?
I think it's far, far to early to conclude that the right-wing political narrative, with it's violent (in the loose sense) narrative, in some way *caused* the actions of any of the explicitly right-wing politically-motivated shooters in the last few years.
All we can say is that right-wing politics are far more attractive to the criminally insane AND evil or homicidal people already existent in the population.
But of course we've known that for a long time, and that doesn't really have anything to do with the recent violence.
Vis a vis violence, I think all we can say is political speech advocating or implying violence will find violent followers, right-wing or left-wing. The sensible thing is for parties/leaders to curtail their own extremists. But we've known that for a long time, too. Thing is: It gets the votes.
So, given that, I think the question of the guy's sanity is more or less moot. Violence really does beget violence, even if the initial violence is just someone else's extremist rhetoric. The process may take years, as private speech turns public, public becomes widespread, widespread becomes institutional and taken as a given. Someone - nut or not - actually taking it at face value and occasionally killing should be expected.
