You are correct. I did teach HS math, Alg1, Alg2, Geometry and PreCalc for about 10yrs before I saw the writing on the wall and resigned.
My watershed moment came when an Administrator with a supposed teaching degree in Phys Ed. (specialty was basketball) informed me one day that the "....kids ain't got no fun in your class and the parents are complaining that you are being to hard on them (them being the kids) and you don't like them because you expect them to work the problems.".
The class was an Alg2 class and the 'unfun' part of the class that the students had been complaining about was learning the basics of a second degree equation. The Administrator then suggested that I should "....consider making the class easier and funner" if I wanted to stay in that particular school; that particular part of Alg2 could not be made easier and therefore "funner" because it is very a fundamental and straight forward part of the subject matter. So to I resigned and went to work in private industry as a consultant.
I also remember the out the window and atrocious behavior that students where allowed to exhibit and actually get away with because it was important to keep the student in school for the cover reason of "it's important they get an education and a HS degree" but the real reason was "the school board needs the money". Also, I do well remember the atrocious insults that classroom teachers had to endure not only from the students but also from a large number of Administrators that seemed to think that most, but not all, classroom teachers where nothing but "overpaid annoyances" to the educational process.
( I did notice that if an "overpaid annoyance" couldn't be in the classroom for personal reasons or reasons of illness and if a substitute could not be found that not one Administrator would 'fill in' for the absent teacher. Other teachers had to give up their planning periods or else be labeled a "non team player and a trouble maker". Which was two well used excuses to "transfer out" or "terminate" classroom teachers.)