the government would know damn well that even the most dedicated UFO cultists and sci-fi gamers would lose their fucking nuts

That was exactly the allegation in the book by John Lear claiming secret alien visitations with the government - that there are multiple species so disgusting or disturbing to human sensibilities, that people would think they are demons and monsters or in some cases puke if they saw them. (not that I believe it, but those kinds of books are fun to read)