If there are UFOs I don't want to know.
We already have a problem with illegal aliens.
Heck, I want to know. Imagine what they could tell us.
Supposedly, "Close Encounters of the Third Kind" is based on a true story. And Jacques Vallee was intimately familiar with all the shenanigans.
In "Communion", there is a short blurb where Whitley Streiber descibes people being sent to another star system on a UFO. Many go insane.
I took a UFO course in college. Almost anything that comes from the government is coverup or disinformation.
Sadly, though, the believer side tends to attract some, well, let's just call them "unusual" people. And that effects the credibility.