> Perhaps instead of lowering the bar to protect the public from what posters here describe as unacceptable beliefs, we should raise the bar.

Which bar is being lowered? What do you even mean by that?

> Perhaps we shouldn't be using pejoratives or sneering at others.

When they are pushing demonstrably stupid, scientifically illiterate ideas as factual, we absolutely should call this out.

> Instead we should seek to have stimulating discussions, question our own preconceptions

When someone brings up flat earth theories it is likely they are doing it because they're -

a) A true believer, deep in a hole of false belief, angry that the government is hiding the flat-earth truth from them
b) Grifting those true believers

Such people aren't challenging preconceptions, they generally either don't understand what they're showing to others as evidence and don't understand what's wrong with it, or they're actively hostile to discussion because their identity is invested in conspiracy theories, or they're actively hostile because any debate threatens their income stream.

> recognize that HN exists within its own bubble. Otherwise, what is the point

I again don't understand what it is you want here? There are no two ways about it, we know that the earth is an oblate spheroid. Getting "outside the bubble" means what? Recognising that there are people who believe otherwise? There are, and they should be pitied. It's not a matter of point of view.

Nobody's stopping you having an amusing little conversation about how a flat earth might work, hell, some of the funniest fiction I know of is set on a Discworld and if you read "Strata" by the same author, you'll find some sci-fi thought experiments around it, and they're great. And nobody's stopping this guy talking about the Silurian hypothesis. In fact surely such things are even more fun if you look at the limitations and objections - how would a Silurian population fit into what we know about the geological record? Someone coming along and saying "Ah, but where's the change in mineral make-up for reason x, y and z, your civilisation would certianly leave that trace?" can add to that, because now you can go back to your hypothesis and account for it! All good fun. It's when you start pushing it as factual and something that did happen, that you'll get people fact-checking.

Honestly your post reads a little like trolling - you seem to be intentionally conflating the intellectual pursuit of stimulating, slightly fantastical discourse with the large population of people who irrationally cling to bullshit.

Look at a different topic for a minute - free energy. Lots of sci-fi exists in which it is posited. Lots of thought experiments exist about it, about the effects it might have on society etc. But when people try to say that they have found a way to do it, we should be sceptical until they show results. And then when they start to monetise this based of hype, should we not call this out? At that point we often see points such as yours raised - change your world view, you should be open to being challenged, isn't it possible you just don't understand the science? But all they really are is exhortations to blind faith, and cover for people who are actively exploiting that faith and the ignorance of others for their own gain.