> I wonder, would you (or others complaining about subcontracting) be OK with it if the prime contractor was totally above board, disclosing the fact that he is subcontracting and allowing you to "vet" the subs?
Yes, the misrepresentation is the key part. For example, if I grant you access to a server that doesn't mean that I want a bunch of randos I never meant having access to the same server as you — if nothing else, you'd want them to have had whatever you consider necessary security training and you'd want your ops people to know that a connection from Romania isn't an immediate sign that you've been hacked.
This is especially true when you're crossing country boundaries and things like IP law or similar concerns vary widely. Most contracting agreements cover things like handling corporate IP carefully and I'd expect at least a request to confirm that this is okay.
Now, there are cases where it might be more forgivable: for example, if I'm hiring you to work on a project which involves an open source component and you turn around and hire one of the developers on that project to add a feature we need, that seems entirely reasonable because it's a) not my IP and b) totally above board that J. Random Maintainer made those commits and shipped v1.2.3 which you're using. Similarly, if you found an artist to contribute assets but didn't give them access to my server or a copy of our code, that seems fine, too. None of that seems anything like the situation described, however.
> I put in some hours in the world of defense/government contracting, where in many cases, the prime contractor never does any work at all. His only job is to "be the prime contractor" but he subcontracts everything, and I mean everything out to others as soon as the ink is dried.
Yes but speaking from experience on the .gov side they do that with the full knowledge of the agency and a contractor will be terminated and banned from future work if they violate security policies such as having unauthorized people access a government system or sharing source code without authorization.