Dawkins and his memes should have been worthy of mention as well as Hawking with his model-based realism. The flat-earth folks just have a different model of how the universe works. It has sufficient predictive power for their purposes and, as a meme, apparently performs a function or it would have been eradicated long time ago by evolutionary pressure. That's probably true for many of the zombies. They have managed to carve out an evolutionary niche that allows them to survive for centuries. Which is rather impressive.