Qualifiers such as evil aren't really useful when there hasn't been a country acting honorably on that stage for a long time, if ever.

Here's a phrasing that might be more appropriate:

"Since we're backstabbers and scoundrels, we should exercise caution around each other."

Do you think it's tough for those regimes to pay someone to do FOIA requests for them? Or to get jobs at government agencies?

We should rethink the concept of a “secret”. If it’s really a secret, it will still be worth the effort to protect.

They are erroring on the side of caution because people have determined secret information from public information - like the energy in a nuclear bomb (censored) by the blast radius (public).

Another example is they want to protect their means and methods. But those means and methods are how they know most information. Often times it's easy to work backwards from they know x therefore y is compromised.

It's a hard problem similar to how to release anonymized data. See K-anonymity attacks and caveats.

https://en.wikipedia.org/wiki/K-anonymity

Surely "keeping things a little more hidden" depends on reliable cryptography.

Not sure if the US with it's torture-base aka Guantanamo and torture-safe-houses around the world really has the right to call someone else "evil", i don't mean that as "whataboutissm" but that human lives are not more "worth" in the US as in Mainland China