As with most things uttered in the name of Disclosure, this claim is ridiculous and has no evidence to support it. To be clear, I support the disclosure of information to the public, not just about the UFO phenomenon, but about all things. The democratisation of knowledge, which in turn becomes power (to borrow from Foucault), is essential to fair governance.
However, many “Disclosurists” are not interested in furthering equality of power. They use the guise of open governance to line their own pockets. Here's a nice a gem for your reading enjoyment that supports my claim.
Being born and raised a Catholic, I feel that I have to clear the air here. Is the Vatican, or any authoritative body for that matter, participating in a conspiratorial Disclosure campaign? I highly doubt it. Does the Vatican believe in extraterrestrial life? Well...for an institution that has been around for nearly two millennia and has a perceived image of being conservative, the Roman Catholic Church is very forward thinking on the matter.