No, some of them are actually insane. It comes as a shock when you encounter them in the wild but a good proportion of teachers actually are utterly insane. It goes beyond mere incompetence because it involves a basic denial of reality.
Some more examples
Banning detention because "studies show kids who don't get detention perform better"
Disciplining me for not performing a fun chemistry experiment even though the way the lab at that school was designed meant it would have gassed the entire school and actually killed someone
Installing a knee high fence to "delineate the boundary of the school", and when several people tripped over it and broke their wrists, replacing it with an art exhibit made of fucking razor wire
Forgetting to hire maths teachers. Dead serious with this one. One school I worked at did not hire any maths teachers. But it gets even more stupid. Their brilliant solution was to take me off teaching science, put me teaching maths, get the guy who teaches PE to teach my science class, and then realising they were short on PE teachers, they got me to teach PE as well and took me off maths.
It isn't incompetence. It's actual insanity.