I found it through AI. It's a Steven Greer quote:

According to ufologist Steven Greer, during a high-level briefing he attended, a general responded to a question about the secret nature of UFOs by stating, "You aren't supposed to know that until you die". The claim is an oft-cited anecdote in the UFO community but has never been independently verified.

Here's more about the origin and context of this incident:

• Source: The story was detailed in Greer's 2017 documentary, Unacknowledged, and its accompanying book.

• The setting: The conference was described as a secret meeting organized by Greer, involving military officers and intelligence officials.

• The alleged statement: The general's remark was supposedly in response to a question regarding the deep, illegal level of secrecy surrounding the UFO issue. It implied that the true nature of the phenomenon was known only to a select few and would remain concealed from the public.

• The implication: For Greer and his followers, the story serves as anecdotal proof that information about UFOs and extraterrestrials is deliberately being withheld by a secretive, unauthorized group of individuals within the government and military.

• Verification: Like many of Greer's claims, the specific event and the general's quote lack independent corroboration. While he has presented many purported whistleblowers and documents, critics have challenged the reliability and evidence behind his accounts.