I would completely agree with this sentiment.
The AGPL is to protect the software you made so it can't be bundled as a service and enhancements locked away because "they aren't giving away the software".
Enhancements to PostGIS would have to be published if it was AGPL. Not literally everything that's on the network.
If someone wants to take community software but not submit fixes then I would agree that they should avoid AGPL.
Unless I miss the point of your comment.