In some cases, yes, but being exposed to several dozens of learned people's perspectives over the course of twelve years of study is invaluable in learning HOW to think and consider information.

Further, having a biased teacher for one term is infinitely less impactful negatively than being stuck with two biased parents who actively conceal information from you over the course of 18 years.

No different than the parent doing the same thing?

I would argue that it's important for them to hear biased opinions told as facts. That turns into a teaching moment when the parent can go over what their kid learned and point on that everyone is a little bias so it's important to remember that when you are listening to them.