Anyone who has worked at the fort can assure you that's not how it works...
Whilst this is true, he leaked only one document related to Australian intelligence, so if there was a lot of sharing between the two then Snowden clearly didn't have access to a lot of it.
Do you have direct experience? Because this is contradictory to my own experience.
When I was in the Air Force we had access to various classified networks at levels up to and including TS. You often needed to be in a SCIF and/or have TEMPEST-rated equipment to log in, depending on the context, but the systems are networked nonetheless.
What I can say is that it's trivial to keep things you don't want leaving a SCIF in the SCIF.
I just find it hard to believe that the military puts all of this information into decentralized air-gapped silos that are completely cut off from the outside world.
Information isn’t useful when it can’t be searched, cross-referenced and analyzed. How does data enter a SCIF? because it obviously doesn’t originate there. Do people walk in with thumb drives and load it into a computer? That sounds like a security nightmare to me
We weren't generating information though, we were generating products. Products (physical or non-physical) get "used" as opposed to "searched".
All the classified/SCIF systems I used were networked, though the networks were physically segmented and most of the classified systems I used did not have internet access. Whether that counts as "air gapped" in your book I dunno, but I never came across anything like the room out of the original Mission Impossible film where the machine has no network access at all. In fact I question the utility of such a machine.
The odds of evidence of a UFO hitting the wrong comms channel and then not being seen by someone before getting scrubbed are staggeringly low. So for someone to have wide access across multiple silos and then hear nothing, one must assume either the conspiracy to hide the evidence of UFOs is supernaturally good or the conspiracy is both still using off-grid solutions to coordinate internationally and is somehow suppressing information that should be in their silo from ever landing in the wrong silo.