I do try to curb the snappy comebacks, but it is tough. :-)
Avoid being snot-nosed but have no fear to rhetorically destroy a dunderhead prof who tries to indoctrinate everyone.
Back in the day, I even confronted a professor with his bias privately and told him that he was being really quite unprofessional by injecting his personal views into things. He didn't like me afterward but I got an A in the class.