After you have watched hundreds, if not thousands of hours, of film about war, disaster, and alien invasion, you notice that some character either military, political, scientist, or shmoe off the street who is smarter than everybody else gives the reason they do not want the general population to know what is going on is because “They will panic!”
In the real world, what if there is a darker reason? People will not go to work. Once that happens, things fall apart as Yeats put it. People will not make the ammunition, people will not pay their taxes, build the escape rockets, or listen to their priests. The exploited are no longer being successfully exploited. The gilt cage is not so gilt anymore.
What if in the real world after hundreds, if not thousands of hours of films, books, classroom, wars, politics, scientific investigation, and shmoes off of the street who are smarter than everybody else, there is a sinister reason that God, the aliens, and The Man do not want the general population to know what is going on. Because they do not know either.