A good professor can have their bias but still encourage critical thinking. I'm from a university informally (?) affiliated to the Southern Baptist Convention in Texas. We often started our chemistry class with a reading of Psalms. We called the Paris Hilton tax/inheritance tax the "death tax" in our economics class as well as in our US History since 1867 class. In my limited experience, professors are able to teach students to think for themselves even when they disagree with me.

I learned a lot but I don't think college made me a "conservative". I was mortified to see our University president on TV demanding religious exemption from birth control in employee health insurance.

No argument here, except to say not all instructors are good teachers. Sometimes we’re lucky and get good ones who despite their biases teach us the fundamentals.