CIA admits Area 51 exists, but won't someone think of the space aliens?

That’s perfectly plausible, but there isn’t any evidence for it that I’m aware of, ie what “secret documents” are you referring to, and what is the evidence that they were deliberately leaked by our military? Don’t get me wrong, I’m not averse to that hypothesis, and suspect that it is probably at least partially true, but you’re making a strong claim (that the military deliberately leaked “secret” documents as part of a concerted disinformation campaign) and should provide evidence for that claim.