Hmm. When you put it that way, it rings a bell. One of the things in the fascist playbook is that the enemy is both very strong and very weak.
Looking through Eco's 14 points of fascism, I could see conspiracy theories fitting numbers 2, 4, 7, and 8, and having a tendency toward 5, 6, 9, 10, 11, 13, and 14.
I hadn't considered conspiracy theory believers to be in any way related to fascists. But maybe I could see it. Both are a simplistic overarching narrative with clear-cut good guys and bad guys (and therefore at least an implied morality). But still, I'm kind of surprised here. I'm not sure I know what to make of this.