What I don't get is why would anyone have to lie in order to prove the earth is flat or isn't flat, what is one to gain from doing such a thing?
Why would anyone lie? Well the devil is a liar from the very beginning. The point of this well played lie is to remove awareness for God -The Creator from you.
Flat Earth Truth clearly points to a Creator and obliterates all these lies and leaving atheism completely obsolete. That's why those pesky atheists here are loosing their mind, because their imaginary monkey world is crumbling down very fast.
Also check out this documentary, it will be of a great help: How jesuits through history worked on erasing God's Flat Earth and The Firmament of His Power
https://www.youtube.com/watch?v=olbyJDou4qQ