Imagine if our reality is not a 'universe' but that this "Earth" itself is the undeniable floor of the reality and that reality actually is fundamentally ice.
Gravity is just a given. What's deep deep down below could easily be what we say is 'empty space above' and is not worth digging into.
Just imagine, just for one second, that the North Pole is the centre of our world and for whatever reason there's a section of the ice-scape that has been carved out here... perhaps to experiment something socially, who knows.
Now imagine that Antarctica is the outer edge of this world and that really Antarctica extends to the rest of reality in a 360 degree rotation of endless possible directions. The North Pole is different magnetically to the south pole as this power is unique to ice and in the end we are doomed to be frozen over (this part is even true in round earth theory).
The original humans, among them a few, realised that the secret to immortality lied in the consumption of the North Pole's water/ice. They also realised that they can only maintain power over the rest if they designed a world model that would make everyone feel there'd be absolutely no point in moving to the center of either pole (I think they found a couple of other 'worlds' on their adventures in what they call the Dinosaur times where there was much less ice and more chaos).
So, there came another issue... Humans were starting to melt the ice caps... This is EXTREMELY BAD for their ability to keep us as farm animals. They are essentially what folklore calls vampires. Vampires are real. The North pole ice/water grants them super strength, speed, intelligence and a lust to abuse us lesser beings over and over again. The more you drink, the paler you get (Obama extremely pale for a black guy, white people run the world etc). So... why not ingeniously combine the invented globe Earth model with the notion of global warming and blame a REAL WAY TO BREAK FREE OF THIS FARM (the greenhouse effect which would melt the fences of our life as cattle slowly) and then to come up with some mumbo jumbo about why the world warming is a bad thing.
The truth of the matter is, even if there are aliens (AKA Werewolves/Hybrids/Shapeshifters/Psychic Telekinetic controlling Telepaths... Idk) that are even superior to the 'superior humans (AKA Vampires)' there seems to be some link between us breaking out of the ice via the 'south way', or rather reaching the centre of the 'north way' and becoming strong as them and us being a threat to them in some shape or form.
Essentially, the flat earth theory is that the ice is the key to reality and the entire globe earth model and everything that is going along with it is a way of keeping us tame.