It's a while since I watched it but I guess it's about the length some teachers will go to if they want the legacy of being the teacher of a great musician. It's about a nasty, revengeful, obsessive character who will stop at nothing to separate the wheat from the chaff to uncover a diamond or to screw over his enemies.

I don't think there's anything to agree with in terms of message since I didn't see in it any condoning of Fletcher's behaviour. Sure, in the end his approach did uncover greatness, but through seeing the toll it took on Neiman, I certainly wouldn't say the film advocates that that is how music should be taught. I also wouldn't say it contained a warning either.

There are several possible messages you could read into the movie, and that lends it depth.