If it were me, I would collect my thoughts and politely voice my concerns to the principal - namely that you do not think that honors English is a proper place for a teacher's personal views on social studies to be imparted and you wondered whether he might agree or if this was an issue you should take up with the school board.
If he is not sympathetic, then I would advise moving up the ladder if there is one to the superintendent's office and use the same polite yet concerned approach. Failing satisfaction there, take it to the school board with a bit more indignation and assertiveness.
By and large, you are liable to find some fairly conservative voices on the school board who may agree with you - even if not necessarily for the right reasons.
BTW, out of a total on my father's side of the family of 10 aunts, uncles, father and step-mother - 9 were teachers.