This has to do with cooperation and transparency. I assume the next retort will be that we are not seeing the "real" documents about UFOs. So far, the documentation we have indicates nobody knew exactly what produces ALL UFO reports but the most likely source seems to be eyewitness perception issues.
"Eyewitness perception issues." Ha ha ha
My friend Rick and I didn't have any 'issues' perceiving the large UFO that flew right over our fracking heads. We perceived it just fine, thank you very much. I don't care if you believe that or not.
I don't know what the nature of the UFO phenomenon is, and I don't know what produces ALL UFO reports. I have my guesses about all that but I know that the phenomenon is legit, and I strongly suspect that governments know that too. They probably think they know what the true nature of the UFO phenomenon is, namely biological aliens from another planet who fly through interstellar space in nuts 'n' bolts spaceships.
If you point to a specific case and ask me if it was a "real UFO", I will say I don't know. If you ask me what they are I will say I don't know. Most people would say biological aliens but I won't say that yet. I don't think the 'ET hypothesis', as it is typically conceived of, is likely. All I will say is that the sort of mundane explanations that clueless skeptics like you put forward don't apply to 100% of sightings, because they don't apply to MY sightings. I know because I was there, unlike you.
Have you seen
Close Encounters of the Third Kind? Imagine yourself as a character in that movie, and you are trying to explain to the main character that his "encounters" were tainted by his beliefs or he had "perception issues" and that there is no evidence blah blah blah. Then imagine how clueless you would look to the audience and to the main character.
That is how clueless you look to me.
The next thing you know 
