You're assuming CIA software engineers are good at their jobs, and that engineers have opsec skills
Those are two big assumptions.
HN is usually pretty logical, so I find it odd that people are jumping to conclusions here.
Jumping from "the CIA is all elite software engineers" to "CIA engineers must have extraordinary opsec" to "if unencrypted evidence was found, the most likely explanation is it was planted" requires several wild leaps.
Maybe the same sort of person who blows up their life by leaking classified information and does it in a manner sloppy enough to at least be accused of the crime is also careless to not properly cover up other crimes?
Also, clandestine service and analyst roles are two very different roles housed under the same agency. Not everyone in the CIA is in clandestine service. (In fact it's my understanding the vast majority are not)
I have no idea if this person is guilty, that's what a trial is for. But I'm not going to say the presence of evidence is evidence of innocence - that seems like extremely flimsy, circular logic.
Then again, I've never held a clearance or worked a government job - this is all just my own analysis based on open source information, so take what I say with a grain of salt :)
Folks may want to read this article:
https://www.bbc.co.uk/blogs/adamcurtis/entries/3662a707-0af9...
(There's also a HN discussion thread for that article: https://news.ycombinator.com/item?id=14500633)