This statement (and the general sense of the author's emotional state) makes me wonder whether the author has actually spoken with teachers or is getting his information from his kids. Kids are just as capable of spinning facts for effect as adults. Or ignoring nuance. Or straight up misinterpretation.
Before "fighting" the school, the first step should be to understand the school's position. Then the teacher's position. Only after the actual facts are on the table should a decision about action be taken.
The author appears to be doing the same thing he rails against the school for doing: treating a single source as the beginning and end of the story.