Yes, folks, you should question everything. This most specifically includes people who request that you "question" your beliefs by means of accepting someone else's.
On that note, however , broad government wide conspiracies don't exist. That's not my theory, that's the theory of a journalist friend who I've known long enough to see he Knows His Shit. A couple of people can hide a crime, and a society can pretend to simply not see something they want to pretend doesn't exist. As far as actually hiding a conspiracy? There become too many people to bribe, too many people to keep quiet, and always too many consciences needing to be unburdened with the passage of time.
The more information you have, the more people you need to manage the information.
The more people you have, the more likely it is that any one of them will break the conspiracy.
Only one person with hidden information needs to leak in order to break the conspiracy.
Quite literally, it is a mathematical equation that demonstrates the success of conspiracies are inversely proportional to the amount of people involved in them. I'm sure some sociology PhD out there has a thesis where they've done a much better job demonstrating it than I have.