I know some brilliant teachers and yeah, they would agree with you.
The 17 year old is now the butt of jokes. Guilty!
I've known a few, and here is the reason I offer this supposition. Back in the early 90's I went back to school for my MBA. I got a chance to talk to a lot of college students who would never wind up in an engineering department.
These kids had been told that they would not prosper without a degree, and they admitted that they had not done well in high school. Solution? Teaching. They were deliberately steered into an education major, and the courses had been dumbed down so that even a kid who couldn't have passed the Turing Test could get a job teaching in the public school system.
These kids are now the the administrators who come up with Zero Tolerance rules in elementary schools, are hooking up with 13-year-old boys in middle school, and creating Antifa Communists in high school who are incapable of determining how they could possibly be the fascists they are screaming about.