Flat earth beliefs doesn't cause harm, but flat earth believers have largely upgraded to believing more dangerous nonsense.

Data or it didn't happen. This really sounds like you're inventing a caricature of your enemy and assigning them "dangerous" qualities so you can hate them more.

Nobody needs to caricature the insane beliefs surrounding COVID (or flat earth), people holding them are doing a good enough job of that themselves.

I do have a few favorites. "COVID tests give you COVID, so I won't go get tested" is certainly up there. I can't say I give two figs about your opinion on the Earth's topology, but this one is a public health problem, that's crippling hospitals around the country.

So it didn't happen?

Exactly - like the "Oklahoma horse paste overdoses overwhelming emergency rooms so gunshot victims can't get tratment" the stories validate all the caricatured biases against middle America as a bunch of ignorant redneck yokels. None of the story was true, but people leapt on it because it resonates in that echo chamber.