People are right to question his teaching methods
Being a teacher myself, I agree with a huge amount that you say in this, but in reference to the last point that you make saying: 'I have to laugh at other reviewers who "question his teaching methods." All we see is discussions of literature and student writing, what is questionable about that? The first "method" of good teaching is to be engaging and involve the student.' This is total rubbish. There were countless things questionable about his teaching methods:
1) He called girls 'skanks' - that's name calling and totally unacceptable, despite what anger he might feel. I've wanted to lose the rag lots of times but you don't let yourself cause that's part of being a professional.
2) As he was their teacher, he ought to have dealt with the disgraceful behaviour of the two girls in the teachers meeting.
3) He physically grabbed at students one a couple of occasions, which is simply not allowed.
4) He engaged children in arguments in full view of the whole class, thereby inflaming the situation, instigating arguments where they could have been avoided and losing face in the eyes of those looking on.
5) He should not have let those two girls stand there listening while he was speaking to the girl who had refused to read.
6) He should have called the girl back after she walked out saying 'I didn't mean it' because he totally lost the confrontation by letting her go.
7) Rather than talk down to her telling her to apologise using a specific sentence, he should have talked to her heart-to-heart and try to establish respect for one another. He needed to make the girl feel slightly embarrassed and genuinely sorry for having spoken to him that way, because in essence she is letting herself down by behaving like that.
8) He should not have gone out into the yard to confront the two girls and make it even worse.
9) He allowed the students to horse around consistently causing 'low-level interruption' - by allowing this, it inevitably led to worse behaviour.
10) He should not have engaged the students in conversation about his private life (when asked about his sexuality) because it's simply not relevant to their lessons, none of their business and it was really disrespectful of the student to bring it up in the first place.
I could go on and on, i think the teacher in the movie meant well but he caused (or made worse than they needed to be) most of the situations in the movie and he simply was not cut out to teach in that tough an environment, if at all, despite how good he was at teaching actual lessons.