You say that like it's a bad thing, and not the defining characteristic of an well educated and well rounded human.

One of the best ways humans have developed for information transfer is rhetorical debate. You're supposed to argue for whatever you believe in vehemently, but critically, abandoning it as much as necessary to adopt a better, more accurate understanding or model.

Unquestioned or unchallenged ideas are significantly less valuable than challenged or improved ones. Arguing for and defending what you know is a good thing, holding on to convictions that aren't improving your life or the life of others is fucking stupid. And the idea that you can't learn something from another human because the medium is the Internet, is certainly a take to read from someone making a comment on the internet.