There are only two reasons for people and organizations to go around and tell everyone about the existence of UFOs: stupidity and greed. The stupidity comes from two sides of the same coin: either these UFO contactees have deluded themselves into thinking they've been contacted by aliens; or they're so lacking in basic scientific education, common sense, and independent thought that they just take the readily available explanation "UFOs are behind it all!" and use it as a replacement for genuinely original thinking.
On the other hand, there's the greed factor: people who promote belief in UFOs because they're making big bucks from it. Remember when the "Mars Rock" crashed to Earth? Consider how long that event captured the attention of the media…and compare that to the media attention focused on the so-called "flying saucer crash" in Roswell. Now think about how much money has been made by people promoting the Roswell "incident," compared to the amount of money made from the Mars meteorite.
Keep this thought in mind when you look at roswell.net and its links to the many Web sites claiming to offer "shocking evidence" revealing the "truth" about the flying saucer crash that took place in 1947. And wouldn't you know it – people are making money from the sales of Roswell books and videos! The UFO museum and tourist trap at Roswell is booming! Hmmm…could it be that UFOs are behind it all?!? (On a different track, you can also look at The UFO Skeptic's Page, which attempts to provide a genuine investigation (as opposed to commercialization) of the Roswell incident.
It's not as if the truth about Project Mogul isn't well known among flying saucer believers. It's just that believers don't want to believe the truth because it's so mundane and unexciting.
Flying saucer believers cling to debunked notions for a great many reasons, among the most notable is the fact that so many believers feel that because they believe things about massive conspiracies that the vast majority of the populace accept as nonsense, they – the believers – are "in the know" and feel part of the team of good guys working to expose the conspiracies and wake up their otherwise ignorant neighbors. It makes them feel that they're doing something good for the community and are "striking a blow for the good guys."
This is important to realize, because while there are people out there who honestly believe such claptrap even though a great many are in it solely to make money off of the true believers. Ridicule should be directed toward all claimants – but the worst should be reserved for the crooks who don't honestly believe but are in it solely for the money.
'Course…good luck trying to figure which actually believe and which don't.