I don't think many are disagreeing that this film is inappropriate for kids.
One issue seems to be - how to punish the teacher?
In that area, it DOES seem relevant as to how "the other side" has been punished in similar situations.
If he doesn't show remorse or reconsider his tactics - then he will have suffer the consequences - absolutely.
He also did not get permission to show the video, and that in and of itself, is reason for termination.