I teach math as well.  (you're right there's no money in it, but I'm not far from retiring anyway).  The government teacher in my school basically teaches communism as significantly superior to capitalism and I called him on it and would debate him during free time (lunch/prep).  One day he told me he would no longer engage in political discussions with me.  He absolutely could not refute my arguments and was left flustered. He'll retire before me.  I hope his replacement is better, though seeing recent new teachers coming into the system I am not too optimistic.