I would offer this prospective (from military years of the 1980s/1990s)...a lot of the senior leadership see this as a ‘joke’ and don’t want their name or their organization attached to any reports or analysis. In one discussion...a commander referred to UFO reports as ‘Leprechaun’ reports.
The chief problem is that you have practical jokers in the mix (like the crop circle crowd), and time/effort is highly wasted.
The answer is in the bible. Yes there are UFOs. No they aren’t from a different planet.
I recently watched all 10 seasons of ‘Time Team’, which was a group of very aggressive archaeologists in England.
Turns out there are crop circles all over England — Iron Age and Bronze Age burial mounds.