Went through this exactly. My guess is because founders select for overconfidence (necessary for pitching investors maybe?) It also ties into founder worship which seems really common (people always dropping reasons founder is some uberhuman).

I just felt like my intelligence was insulted. I also found out a lot of the other people who "bought into" the "mission" were really just playing along.

We also did a lot of "agile" that wasn't agile at all. Make "MVPs" that weren't shippable, do work in 2 week "sprints" but never talk to customers for months etc

Like you said, I'm much happier at a place that takes a critical eye at its own projects, is actually willing to change the plan according to feedback rather than assume we're building the founder's "vision", actually dont' take ourselves too seriously, etc