Mrs Carey is a bully. She is totally one-eyed and wants to force her view of music on all the kids unfortunate enough to come within her domain. She's probably killed more interest in music than she's evoked in classical.
Well, you're clearly not one-eyed. That's such a an objective, balanced judgment you've given. And if you think Emily is a "born musician" you weren't actually watching the film (she did do rather a lot of practice) and you know nothing about what makes an outstanding musician. You'll grow into the lady who famously came gushing up to Arthur Rubinstein after a concert and said: "Oh, Mr Rubinstein, I'd give twenty years of my life to play like that!" He replied: "Madam, I did."
Lighten up people. It is a MOVIE. Do you think that the camera crew just happens to turn up whenever their is an discussion or an issue. Do you think that there is a reason that the kids never happen to notice a film crew in their school. It is reality TV.