Either way, the message is clear: "don't fuck with us."
Tons of stuff is classified, sits in a safe for years and years, and eventually just gets shredded. Probably 99.99% of it. There is a cost to declassify documents, but for the mountains of stuff that never gets declassified (because it just goes into the memory black hole) there is no cost.
Honestly I think there is just a CYA mentality to just slap SECRET on documents rather than trying to thread the needle and figure out the exact correct classification. In theory these documents should be classified at the paragraph level, and in that case things like public statements by public figures would be unclassified even if they were a part of a highly classified document.
People will properly classify things if there is some reason to, but day to day it's not trivial to do and in the end nobody sees their goal as 'get the exact right classification on everything' vs 'find a terrorist or figure out what russia is planning'.
We had a joke that each birthday card has to either go to the security office and the personnel office to get stamped [secret] or straight into the shredder. And that's simply because by the time it goes around and everyone sings it you get a list of individuals, any list of individuals according to the regulation counts as a roster, and all rosters are classified.
The cost of classifying documents isn't in keeping them secret as the only cost of that is your storage space, the cost is in the man hours required to go over each line and paragraph and determine if it exposes any classified material, source or method and then classify it accordingly, beyond that you also have the added cost of tracking the dissemination of classified material as distribution and access lists have to be maintained and approved, copies tracked (most importantly tracked down for EOL/recovery) and you also have to do an impact analysis every time you change the classification or declassify it.
So to simplify things you shred everything you don't want to keep and give the highest baseline classification you/your department is operating under to any other document you might want/need to keep for the future regardless if it's an actual intelligence product or a group lunch order.
After that, it gets vented out through at least three different chimneys--with armed guards on each one, to shoot anyone that sniffs too deeply.
All because of something that probably happened in the 80s, when someone was able to recover secret information from a paper document that had been burned in an insecure way. I mean, if the Soviets could eavesdrop on a mechanical typewriter, and all methods and practices are always classified on all sides, how would we ever know whether anyone can use packing tape and a relatively abundant type of medical scanner to read words off a burned page or not?
(the fictional portions of this post are based on an amalgam of true stories)
This. You have warehouses A, B and C full of documents. Let's assume that B and C are full of birthday cards and stuff that doesn't need to be classified. There's an operational cost to those two warehouses. With classified info it's not just some 12.50/hr security guards and lighting. You have tons more compliance auditing and other policy stuff that pushes up the cost. When some unlikely event finds a bug in your security protocol that results in a revision it costs 3x as much (because you have 3x as much to secure). If it's mixed material there's a huge cost associated with periodically determining what's what. It's no expensive compared to other things but it's a big unnecessary cost. Imagine if FedEx's policy was "employees should be hard on equipment whenever possible". It's not all that expensive compared to employees themselves but broken equipment costs money and slows things down. Classified info is the same way. Stuff should be classified per a "need to classify" standard the same way classified info is shared per a "need to know" standard.
That said, the NSA loves looking for patterns and/or needles in haystacks and may be worried about other organizations doing this to them. It would not surprise me if a lot of the stuff that seemingly needlessly stays classified stays that way to make it harder to build a big picture view. They may see the same kind of scaling problem as the one between non-networked license plate readers on toll booths (few data points, hard to build big picture) networked license plate readers on every police car and traffic light (tons of data points, easy to build accurate picture).
Regardless, there's much lower hanging fruit when it comes to government inefficiently using $.
When you declassify a document you need to go over every word, check if it related to any source or material that cannot be declassified or ad hoc declassify additional material (which is why many times when there is a FOIA request for a document you can get more than what you ask for) go over every codeword and dig up everything that relates to that and run the same process on that material also. After that once you accepted the declassification you go on a hunt and collect all copies and revisions to ensure that there are no copies other than the final "declassified" one.
Declassifying documents is like pulling a string on a sweater you start pulling it and if end up unraveling the entire thing this is why the often redact whole paragraphs and even pages since the effort is too great and you don't want to risk leaving breadcrumbs. Counter intelligence and OSINT agencies often practice on investigating declassified material and to see if they can gain any "unintended" intelligence from it and often they do and the declassification procedures are updated.
Governments need some level of secrecy to run, the level is dependant on the department and the subject but it secrecy is important none the less, people often don't realize just how many things can easily be screwed up by a tiny leak.
"Leaking" small pieces of information that doesn't seem relevant, over time, might help someone construct/discovery something big.
Example,exagerated: person A studies genetic deficiences. Person B studies some new yeast. Person C works as voluntary in vaccination campains in Asia. A "dinner receipt" gets desclassified revealing that now they are working together. A person D, Asian descendant, dies with some new untreatable disease while working with the former 3, and his death is also declassified with more details than necessary...
All these facts with a 10 year span. Could ring some bells, no?
[0] http://www.npr.org/sections/thetwo-way/2014/05/20/314231260/...
Polio vaccination in Pakistan is utterly hindered because the "village elders" and the usual suspects spread nonsense that the vaccines were donated by Israel and it's a Zionist propaganda to turn the male population gay and sterile.