That's part of it, and it's certainly why so many of them have persistent chips on their shoulder about shit that happened in middle school (looking at you, Scott Aaronson).

The other part is that trying to construct all truth from first principles is a hopeless endeavor for a single person or even a group of people. The rejection of institutional expertise - and the collective knowledge of failure modes that is embedded deep within institutions - leads to a lot of predictable failures.