Much like technology, or natural resources, until the various governments can control what people think, believe, or get to interact with where aliens are concerned, there will always be silence and secrecy.
The notion that there are superior beings, with superior technological ability, and superior intelligence might upset the balance of power here on earth for a lot of reasons.
1. Governments would have to confess to the secrets they've kept for years.
2. Organized religion would have to confess that they've lied and marginalized anyone who spoke the truth, for centuries.
3. The media would have to confess their knowledge, and complicity to the marginalization of people who have discussed extra-terrestrials, or UFO's.
4. A lot of people who ostracized neighbors, and friends would have to do a mea culpa as well.
5. Then there's the military's confessions, and I would wager that would be quite the laundry list.
On top of all of that, there would be the frauds who have never had an Extra-Terrestrial encounter all saying "I told you so."
Does anyone really want disclosure? In all honesty I really don't. I do not want the frauds, fakes, and phonies in the realm of the paranormal to be given validation by anyone. Could you imagine the nonsense?
If you think the merchandising and packaging are tiresome now, just wait til the day comes when you can go on line and buy a t-shirt that says... "I went to the Vatican, and all I got was this stupid Alien Starchild T-shirt."
Do we REALLY want full disclosure? I certainly don't. I'd rather have it all be a figment of the collective unconscious imaginations of humanity, than have it be something that a small group of humans gets to control.