Flat-earthers, and I see it as the most unhinged for one simple reason:

It seemingly has no -- Stakes?

Like

With every other conspiracy, whether it be related to 5G or Fluoride in the Water or Vaccines or whatever, there is ~someone~ who is consolidating a shit-ton of power or wealth through their conspiring, y'know?

But with Flat Eartherism.... ? Like. Imagine you got control of every educational institution. You use it to convince people the planet is the wrong shape. And by doing that you gain.... -- What exactly? It just seems pointless? We know what people do when they have power to manipulate people on that level, because history tells us. And they generally don't bother with the shape of the planet.