What can I do about this?

I'm not exactly sure. However, you could write up a petition about what's going on and have the students(or who ever agrees with you) to sign it. I would then take it to the principal. Explain to the principal how this teacher's actions are affecting you. If the principal idea doesn't work, I believe the next step would be the school district's superintendent. I would agree with you, teacher is way out of line. I hope this helps some what. Don't be afraid to stand up for what you believe. Good luck.