Do you speak up? I was also an A student and used to fight my leftist professors tooth & nail (it became a bit a theater with a few of them)— the professors actually loved it and I’m sure I gave the students something to think about (which is more than the usual classes did). It’s not easy, but winning minds never is.
Depends on the professor. Good professors, even when they are hardcore lefties, may not agree with your pov but will give you a good grade if you can support your arguments.