I wonder if it is some kind of frustration burst release that finds a convenient path of list effort in the far-right propaganda. Like when people get furious alone inside their own car and call everybody names, or gamers threatening your life online after some loss, because there's no perceived emotional consequences so they don't need to restrain themselves, same idea but more extreme. I don't think most of those people would have the heart of doing such horrible things if they were in front of their target and had to face the inevitable human empathy. Sociopaths with zero empathy are probably much rarer than Trump supporters.