That is a very specific political way to rationalize his actions. If other rumors of him not being a very politically involved person are true, then it can be more simple than that. Day one of being eligible to vote at 18 a lot of people register along the same party lines as their family. He could have checked the Republican box just simply because that’s what his parents were. Over 2+ years from then, who knows how he developed, what his influences were, and what kind of person he became. In any event, something lead him to be a very sick individual.