You don’t accidentally publish the list.
At very large organizations, sharing files easily is a pain in the ass. The available tools are usually tied to your Active Directory, which means you have to know who you’re sharing with, or at least have some idea of what permission groups allow what access.
To share documents appropriately, you still have to do the hard work of finding out who and what permission groups you should be sharing with, even if that means coordinating with other IT teams to make sure you understand their permissions structures properly.
Or you half-ass it, and put the document somewhere public and hope the link doesn’t get shared beyond your control (or found).
I guess I’m saying it’s not intimidation, accident, or resistance — just laziness and stupidity. Both of which are not unfamiliar ground for this administration.

Yeeeaahh… At my org our default security policy for all of our site collections prevents sharing outside of our domain, and requires managed devices to access our SharePoint.
To share things outside of our org via SharePoint, a site collection with a different security policy has to be created, and only admins can control the sharing. We can only share with people who have some sort of identity service that can federate with ours.
No user is granted above contribute access, and sharing is turned off. (People can share links, but they cannot change the permissions of an item to share it.).
Theoretically it’s possible that a SharePoint can be created that allows public access, but to my knowledge we do not do that.
OneDrive files cannot even be downloaded by external parties (although they can be viewed in the browser!), and Teams workspaces are also not accessible externally unless by special circumstance.
I would imagine the federal government is… well, hopefully at least as locked down as my work.