>you're gonna end up with grouping all people who think like that in a community
That's exactly what not banning them is doing! Not that I think flat earth content should be banned, as it seems to be mostly harmless. Before the internet, people who believed in fringe conspiracy theories didn't have a good way to coordinate and group together at scale.
Hell, even in the mid 2000s, after the internet had been around for a while, fringe communities tended to self-segregate in their own forums. They group together and formed echo chambers, yes, but they were also insulated from broader society, and therefore had little ability to acquire new converts. It was recommendation algorithms that popularized fringe ideas, by pushing them to bigger audiences that otherwise never would have been exposed to them.
I think that's really the core of the problem, recommendation algorithms. The algorithms don't know how reliable or accurate the content they push is, they just push whatever the machine learning model predicts will keep the user engaged. I would much rather group the people at the fringes into online ghettos than have them roaming the broader web and spewing their nonsense to anyone the algorithm recognizes to be vulnerable to conspiratorial thinking.
As to examples of cracks in the paradigm is respect for empirical knowledge, I don't think you have to look far. The rise of political extremism has resulted in more people on the far right and far left, ideologies that are hostile to the notions of nuance and cool headed reasoning, and thrive on emotionally driven messaging. More than 15% of Americans believe in QAnon, and nearly a third believe in the election conspiracy.
Meanwhile on the left, you have rhetoric that is increasingly hostile to data-driven approaches to problems, instead preferring "lived experience", ie anecdotes. You have cases like David Shor's firing for daring to tweet a study from a respected scholar that appeared to challenge the zeitgeist at the time. Many of these people are highly educated, or even academics themselves.
And that's to say nothing of regular old snake oil that has nothing to do with politics. Essential oils, healing crystals, you name it. Misinformation is on the rise, and most of the population is not equipped to deal with it. Maybe this is a temporary growing pain, maybe not. I don't think there's any way to know for sure right now. But we do know that for most of human history we have lived in the darkness, so it wouldn't be terribly surprising if we end up returning to it.