Alternatively he is just trapping people psychologically: once you have agreed with someone you will later rationalise your agreement to avoid cognitive dissonance, and you keep doubling-down on that agreement . . . since confronting your false beliefs would be so psychologically difficult. https://en.wikipedia.org/wiki/Cognitive_dissonance https://ideas.darden.virginia.edu/talking-ourselves-into-it

Edit: to fight it, perhaps create a psychologically plausible excuse for why everyone fell for his shit? Give people an out.