Both of you could be right. There definitely does seem to be quite a bit of tribalism.
How often is something TOTALLY B.S.? I tend to see more shades of gray than black and white. It can be that MOST of what you studied was B.S.... yet there could have been parts that is true. I find that absolutes usually are not true. There of course are exceptions.
So the journey to learn something can be important and can offer perceptions at truth you might not have seen from another angle. They can likewise conceal truth.
I tend to not close my mind to new information. The key though is whether it is NEW information or not.
Hearing things I dislike or disagree with and then going NAH NAH NAH could make me miss the only new information that was there.
Kind of like information prospecting... gotta throw out the junk rock to find the good ore. Yet if all I do is look and see only the junk rock, how can I ever find the good ore?