According to
wikipedia he was more into Zeitgiest than Sarah Palin.
This might put him somewhat into the Glenn Beck camp, because of the conspiracy theories. Zeitgiest worships Lou Dobbs and endorses Ron and Rand Paul.
Given this information, and the fact that he seems to have had it out for Gabrielle since 2007, I find the charge that it was the right wing's violent rhetoric to be unlikely, though once again, the conspiracy stuff DOES link him to Beck, at least indirectly.
One COULD make a Tea Party connection there, though without more information, that would be pretty thin.