Generously you could say they're reacting to the "real danger". The danger to them personally is that someone else does better at a currently fancy project and appears more capable than them to others.
I dont know why your up-playing their IQ. there may not be a ton of forrest gump tier dummies, but they're often profoundly average people.
I've done consulting at F500 companies and was consistently not-impressed by director levels and above, dudes in tech for 30 years and didn't have an understanding of what "production" meant. Outsourcing literally their basic day to day job responsibilities to Accenture and McKinsey to the point where pretty much anyone reading HN could have been in their role.
A lot was "flash" -- looking good, speaking grandly, and sticking to broad approaches that they could assign to a technical senior manager or contributor. And a lot of the time, to be honest, that worked: sometimes you just gotta motivate people with big gestures. But once it became time to actually get outside of the box and generate new ideas they were stuffed shirts.