Here me out on this one, The government of the USA has the right to withhold information especially when it involves a threat to national security disclosing such information or confirming that their is Gold in Fort Knox will make that place a known target for criminals or even terrorist who really wants the economy of USA collapse, saying that there is no Gold in Fort Knox will definitely give a massive panic but the most brilliant way to avoid this is stating that the gold is on an undisclosed place well guarded by the government.
You are 100% correct, but why not disclose this to a reputable citizen that are not associated with the American government? They do not even have guards inside Fort Knox, according to a previous guard that worked there. All of the security measures are on the outside to prevent people from knowing what is going on in the inside.
It would be stupid to store all your Gold in one place, because one Nuke will render all that gold worthless, but some of Americas most precious original documents are also being stored there.
