That’s actually exactly how it started. 4chan started memeing about flat earth, pretending to take it seriously. But then the idiots found it, and Poe’s Law fused with the Dunning-Kruger Effect.
The idiots couldn’t tell it was sarcasm, and thought it was serious. Simultaneously, they thought they had stumbled into a huge conspiracy. So then the flat earth stuff took on a life of its own, and the conspiracy became self-sustaining as idiots began a positive feedback loop.
At that point, 4chan took a step back to watch, and just sort of let go of the reins. Because at a certain point, reality is more funny than any memes you can come up with, and this was the peak of entertainment for the people who started it as a joke. Seeing their joke take on a life of its own was better than anything they could have imagined.
It’s like the first kid who came up with the “Marilyn Manson had ribs removed so he could suck his own dick” lie, hearing it from someone from another school for the first time; The excitement would be unparalleled, as they realize just how large the joke has become.