One way or another, they've been lying to us for decades now. It pretty much breaks down into, either they know about aliens and they've been aggressively lying about it for decades, or there is no evidence of aliens, in which case they have almost certainly had a hand in creating the news and foisting it on the world. Somebody is making all those faked videos and photos.

One can try to craft scenarios that try to split between those two branches, but I haven't come up with anything very credible. For instance, it is just faintly possible that this whole thing is one gigantic ten-thousand-way misunderstanding, but even then I find it hard to believe nobody in any position to get to the bottom of such a thing did and then did something sensible with the result.

At this point I pretty much won't believe anything they say, in any direction. No matter what the truth may be, "they", for all suitable values of "they", have burnt all their credibility already. No matter what the truth is, "they" have clearly been throwing up vast quantities of smoke for decades now.

I say this without much opinion on what the truth is, because this is independent of any particular person's beliefs on the matter. Nor do I have strong opinions on who "they" is; yes, I'm using it as a pronoun without a referent, but at least I'm doing so knowingly. I don't know who exactly is doing this and "they" is just the grammatically-correct way to express that in English. No matter what you believe and no matter what the truth actually is, I think this is a fair assessment.