You believe JFK was killed because he was going to tell the truth about a conspiracy of the shape of Earth?
JFK was a key figure in promoting funding for NASA in the late 50's. Trillions of dollars were poured into what was essentially a fruitless pursuit of space exploration. After numerous early disasters and technological failures NASA's administrators soon realized that space exploration was essentially impossible. With pressure mounting from political, public, and militaristic sides of the spectra it was deemed necessary to abandon serious space research and create an illusion of space travel to justify its spending. NASA was pressured from all corners of the government to succeed.
Winning the space race wasn't just about getting into space, but demonstrating to the world America's technological ability to create nuclear tipped intercontinental ballistic missiles. That was the real purpose of NASA. The idea of Mutual Annihilation was key for American dominance on the global battlefield. Without the ability to send nuclear missiles into space and half way around the earth at any desired moment, America's threats would fall on deaf ears.
The white lie of the Conspiracy grew into a national security issue beyond all others. It was considered acceptable to protect the dark secret of the nation's weakness even if it meant assassinating the president himself.