A ruling government can't afford to publish history in a version which lessens its' chance for reelection.

Smartass Disciple: Why do arrogant people like to say complex words ?
Master of Stupidity: Ask them straight! You'll get a simple scary version.

Great men look greater than yesterday.

There is no single truth in a world ruled by many political parties.

For the sake of popularity, vote, and reelection, most governments remain secretive to the public about the truth of alien contact with mankind. For them, it is better like that than being thrown from the throne.

In any government, interests precede truth.