This is absolutely fascinating. I’ve been trying to develop a theory around it in my head for months (if not years!). I think you’re absolutely spot on!
I see people like Nunes, Jordan, Graham, McConnell etc., whether we agree with them or not, they are elected representatives who are palpably not un-intelligent men, yet they seem to revel in the image of them coming across as total morons. Just objectively moronic.
To develop on your great piece, I think it has a lot to do with ‘authenticity’. Politicians attempting to appear SO ‘authentic’ that they try incredibly hard to mirror their voters — so much so that they end up with a “you’re an idiot, I’m going to pretend I’m an idiot too so you think I’m like you”