Which obviously can't be true or it would be inaccessible and thus utterly useless.

Why? It can still be connected to SIPRnet or JWICS.

Or customers can get a Direct Connect from their existing facilities into the region. I presume the USG has plenty of fiber straight into these new datacenters and I'm not sure why Amazon wouldn't allow Direct Connect.

As someone else mentioned, perhaps this will get contractors to stop using public S3 buckets to share data.

That’s not “air gapped” if it’s connected to another government network.

It's air-gapped from the Internet.

The term “air gap” does not directly imply anything to do with the Internet (doesn’t exclude it, but it applies more generally than specific networks). Yes, IC uses it to signify high/low networks, but the original usage of the term was to indicate a machine with no direct connection to the outside world. The theory being (since proven wrong), you can’t exfiltrate data remotely from a device not connected to a network.

What if it’s submerged in coolant?

JWICS/SIPR/NSAnet/etc. are air gapped in that terminals are not allowed to be dual homed to any other network or to each other.

Yes, I know the inteligence community uses this definition of air gap to signify the barrier between high/low networks, but I kinda feel it misses the point of the term. If it is networked to the outside world, even securely, I feel it kinda misses the point of the “air gap” connotation (aka requiring a “sneaker net” to get data in / out). I’m likely being pedantic though, so I upvoted you as you at least gave a good response unlike others.

It’s useful insofar as it’s connected to itself, allowing individuals and companies to share data and compute with one-another, where data can ingress/egress manually but travel the network between VPCs automatically.

It might also mean that the cloud is connected to networks that are not, themselves, Internet-routed. For example, users of the Secret region might have leased lines connecting airgapped computers in their own facilities directly to the DC for ingress/egress.

It might also mean that the network is connected to a “different Internet”, like MILNET.

inaccessible for whom? the public internet isn't the only (inter)network that exists.

They likely connect via encrypted leased lines.