I'm curious what is in the redacted parts that still needs to be classified? Surely nothing from 1974 is still state-of-the-art today. Surely no covert operatives are still in danger from the 70's (though I guess it's possible).
For the specific purposes of redaction, it's not about whether something "needs" to be classified. They redact what is classified. The decision to unclassify lies elsewhere.
And the reason it hasn't all be declassified with a blanket order is no doubt simple bureaucratic conservatism. No one is going to get an award for "brilliant work in declassification", and the last thing any spook wants for her career is to be yelled at for declassifying something embarrassing.
Statistically, real threats are rare, but ambition and corruption are
common. Overwhelmingly, the purpose of censorship is not the protection
of national security, but the protection of individual careers. That's
not ideology, but mathematics. Because there are very, very, few true
national secrets, but a huge amounts of information that someone would
like to bury for one reason or another.
I don't think any kind of careerist conspiracy is required to arrive at a culture of over-classification.
The habits of anyone working in any kind of role involving information security are so utterly obvious that they barely require discussion.
You make sure your office environment is secured, don't leave papers on your desk. Don't duplicate information more than necessary. Full disk encrypt everything. Never email documents without encryption. Don't use USB sticks without encryption. Know who you're talking to on the phone. Don't ever talk about incidents, jobs or the specifics of what you do.
Now think about people who reflexively do all this stuff and consider: a) how strong the urge to classify by default is and b) how much more work it takes to be 100% sure a document is safe for release.
You've just described a careerist culture, if not a conspirace, it seems to me.
What's the difference between reflexively classifying everything as highly as you can, and routinely covering up inefficiency and waste, and maybe a little graft on the side? Pretty much nothing.
1974 is only 40 years. The terms "career politician" and "career bureaucrat" apply everywhere; someone recruited, say, right out of school, could easily still be working. That's to say nothing of anyone those people may have recruited.
Same goes for technology. What was done 40 years ago may not directly apply, but it might give clues to what's around today.
