Respectfully, it does not matter why. Americans have spent the better part of a decade navel-gazing on this shit, and the best answer seems to be that they were bored. You do not have time to dig deeper than that. Mock them for it. Lay bare what they’ve bought into. Make your shame about them clear.
Does that make East-Germany’s #AfD or #BSW supporters #Nazi’s? Again, potentially, but mainly inadvertently. Are these people frustrated and angry? Hells yes. The question is why?