Dismissing any and all ridiculous thoughts that the Earth is flat, I will address the "govt conspiracy" angle.
Perhaps every govt in the world who has approved space travel has somehow gotten on board with each other to completely pull the wool over all of the Earth's citizens' eyes. I'll let that slide. Although, considering the space race between USA and USSR back in the day, and their lack of communications during the wall era, I find this impossible.
So, if the govt is conspiring to hide that the world is flat, why allow private citizens to venture into space on their own, where they will see first-hand that the world is round?
Discuss.