But so-called progressives have a strong tradition of believing things without actual knowledge. A lot of it is a reflexive reaction against either the right or authority, assuming that if they think it's true, it must be false.

Whether it's climate doomerism, "CRT is not in schools" + "CRT is just about teaching history" + "CRT is only an obscure grad-level legal theory" (not even self-consistent, and all wrong), "sex is a spectrum", "Latinx" (thanks guys--have you heard about this cultural imperialism idea?), and so forth and so on, there is a ton of mindshare in progressive circles for things without adequate knowledge. Indeed, although it's practiced more on the right (while simultaneously being denied and decried), there's a whole set of ideas about why this is perfectly okay from "narrative" to "speaking my truth" to "dismantling systems of oppression" (applied to the standard that you should base your beliefs on actual knowledge) to an emphasis on deplatforming rather than robust counterargumentation.

That anti-progressives who feast on Fox "News" are often so far off that it's hard to stop laughing long enough to rebut them doesn't make the progressive norms any more correct.

So that it's not based on knowledge isn't at all surprising. It's been like this for years.