Here's what might spoil it for you, should you believe the BS that's being spread around this stinking pile of excrement: It could have actually been OK if it hadn't been so laughably impossibly ridiculous. Perhaps if it had been set in the fifties or the forties when people had much less developed consciousness of human rights? But even so...
I suppose the moral/lesson we are supposed to learn is... if you can't warp your students enough by abuse to force them to become great musicians then it is perfectly alright to discard or destroy them in the attempt.
This glorified tyrant and bully can himself only produce music at a grade one level and so because he cannot 'do' he 'teaches?'
He does not teach, he does not inspire; he withholds approval, negatively reinforces and rules by fear, and is feared rather than respected. I would have a difficult time to point to a single (pedagogical) scene in the film that had any merit whatsoever or was worth watching for any reason. Maybe I should say that its evident popularity may be evidence that we are truly living in the end times... ha!
See the film if you want to be current, but please decide for yourself from watching it and don't believe the hype about its 'genius' or 'brilliance.' It is not either of those things; it's a poorly written, sad joke.