"That's information relevant to your job.
What was Manning's job, did it require access to more or less information?"
SIPR and JWICS are not caveated systems. If you have SIPR access, you can in theory access anything on that network. I can access DOJ-related files if I choose. And have on occasion. That's where the really creepy [...] is at.
Only SAP/SCI level programs have restrictions, other than website managers. And you have to be read into those. But once you are, in theory, you could make copies.
"Manning is a Private, are you?"
Our junior enlisted intel troops are read in at a higher classification level than I am.
The restrictions are not on how much time you have served, but how much time you have left remaining on your enlistment (for junior enlisted).
"Manning exhibited lots of behavior that should have been a red flag regarding his access to classified information, do you?"
This is where I will agree with you in part, but it does not relieve Manning of his contractual obligations to protect classified information.
"Can you access sensitive information at State, DIA, DoD outside USAF, outside of specific programs you're involved in?"
If it's on SIPR, I can access it. The exception being that some sites require webmaster authorization. The stuff that he released was available to anyone with SIPR access.
"It's like the threat model was never even built when these systems were being cobbled together."
To the best of my knowledge, there isn't a threat model to defend against blue forces. Because by giving the enemy information we only hurt ourselves.
Perhaps the answer is to take Manning up in a helo, and throw him out. Might that serve as an effective deterrent?
"I don't. Doesn't sound like there's any mechanism in place to stop someone like that."
To find the answer to that question you will probably have to join the military and get cleared to the point where someone would be able to legally answer that question if you were to ask it.
"Any light that's shed upon the military is good, imo. We spend way too much money on bombing brown people, rather than developing minds and infrastructure here at home."
So you'd be a fan If tomorrow someone were to leak the command and control procedures used by the US regarding nuclear weapons? Made it so that anyone would be able to decode, or even replicate, nuclear C2 orders. What about critical nuclear weapon design information? published on Wikipedia?
Oh, and certainly the names of everyone who is spying for the US should be made public. The people have a right to know.
Be careful. At some point I suspect you are going to forget to breathe.