In general, it's a weak argument, although I hear it often. "There's no point in trying to keep people from doing X, because if they can't do X, they'll do Y, which is just as bad."THAT IS NOT MY POINT. My point is that the real issue here is an abusive teacher. The fact that he used religion to belittle the student is neither here nor there; the real issue in the story you told is that you have an abusive teacher, not that you have a teacher who doesn't separate church from state.
Or to put it another way, this isn't really a church-vs-state story, this is an abusive-teacher story.
Get it now?
Alex