From that article in th Atlantic linked above:
"What’s clear is that the Capitol riot revealed a new force in American politics—not merely a mix of right-wing organizations, but a broader mass political movement that has violence at its core and draws strength even from places where Trump supporters are in the minority."
It feels to me as if living in a place where your views are in a minority might in itself cause you to want to do something elsewhere which was more truly what you thought/felt/believed. Sort of "Yes, OK, Biden won my country and that's not right, but at least I can do something to make him look small". I can see being that way myself about something I felt strongly about.
I mean, Blair was Prime Minister, voted in by a majority of some sort I now forget, and I lived in a very Labour-supporting area at the time, but that didn't stop me feeling so strongly against his taking us to war in Iraq that I went and marched against him in London. Did no good.... But if someone had been there encouraging us to storm parliament and hang him, I might well have gone along with that as well.