Flat earth is not just a conspiracy, it is an outright religion. Any attempt to try to convince the adherents of that faith in sound logic or natural law is as productive as trying to convince an elderly tribal medicine man to stop molesting children to "cure them of demons". Luckily, the latter hurts others, the former only hurts themselves, so why expend any effort trying to educate individuals who are beyond education. Instead, let's build them a temple. Maybe in NYC. Then intelligent people will recognize a little easier that it's not worth wasting effort on members of the FLERTH church.
ETA: It definitely can be amusing to see what some of them believe though. [LOL] Sounds like a nut.

