Jason Flare
NES Member
Motive and choice of target only needs to make sense to the attacker(s) and likely wouldn't make sense to people thinking rationally. What is going to matter is who these guys associated themselves with in the past, or continued to associate themselves with as they carried out their attack.
Statistically the nut-heads more often come out of the left wing but it is certainly possible that a libertarian has lost his marbles and is fed up. I just wouldn't bet on it.