It has not been reliably established, to my knowledge, that the perpetrator is "right-wing".
Furthermore, a careless writer who doesn't define his terms.
Does he hold the traditional view that on the left of a line is Stalin/Mao/Pol Pot and on the right Hitler/Mussolini? If so, he's a moron, because those two points complete a circle at TOTALITARIANISM. Extreme Left = Extreme Right.
The correct view of a freedom scale is a straight line:
(Left) Totalitarianism >> Conservatism >> Libertarianism >> Anarchy (Right)
The way this guy puts it, the shooter is basically one of us, conservative -- just a bit too much so (ergo, "right wing"). It's an insult!
Unlike our totalitarian counterparts, we on "the right" revere Life and Liberty such that murder is anathema for us.
Careless, sloppy writing. And sadly the norm.