Just scrolling through the reading room, you'll find tons of stuff like This

Which is published as "declassified" but it's just a photocopy that was used in some other report.

There's tons of click bait stuff that shows goofy diagrams like the main post that aren't primarily from the CIA, but just photocopies of some nut job book or article that was included in some report at some point (usually now devoid of its original context because the FOIA request that declassified it was too broad).

If someone says "give me all documents pertaining to UFOs" or "give me everything you have on the cyclical universe" they'll only declassify and release the scans of articles and books that were included in a bigger report.