how "flat-earth" became a thing: possible origin stories

it started as an experiment in belief manipulation
When I first started seeing people online talking about how "the earth is flat" my first reaction was, this is somebody's epic trolling project. This has to be some kind of thesis in online psychology or something like that because the idea that the earth is flat is one that some cultures have experienced, and then they unlearned and discarded this belief once they evolved in their science and got new information. So the fact that there are (supposedly? maybe the joke is on me) people once again arguing how the earth is flat could possibly be the result of someone trying to find out the best way to spread the most outlandish idea
it came into existence to be used to discredit alternative thinkers
...etc...