This makes no sense.
You know that’s just the cover story.
Not going to defend the policy, but it goes back a ways. I was first briefed on it while doing a stint as a govt contractor in 2004 or 05.
The principle involved is that something isn’t really declassified until the classifying authority in the government actually declassifies it. Materiel that is in the public domain, but which remains classified, is still classified and is expected to be treated accordingly.
It seems completely counterintuitive and zealously bureaucratic, yes ... But hey, that’s our government, right?