Being paid for doing work has nothing to do with extracting rent, which is the practice of inserting yourself as a middleman so other people have to pay you "rent"[1] where none should be required.
The entire idea behind writing a Service as a Software Substitute[2] is about extracting rent.
I understand Stallman's dislike of SaaSS in [2], but I fail to see how it meets any definition of rent-seeking. People who provide SaaSS are using economies of scale to offer services that are desirable to some, because they're offered at a cost that is less than the cost of developing and maintaining their own private solution. There is certainly a loss of freedom in using these services, as Stallman points out. But rent-seeking, not so much. Users of SaaSS need to decide whether the cost savings of using SaaSS is outweighed by the freedom they give up. Nothing more, so far as I can tell.
Perhaps you should have read that wikipedia page before so helpfully linking to it. There's nothing about "middlemen" there. "Rent" is political economy jargon; it's not just a synonym for "distasteful practices". Adam Smith wasn't complaining about shopkeepers or shipping companies, and he certainly wasn't talking about "back end" software services. There is no royal decree enforcing how such services shall be provided. If you don't like AWS then use GCP.
I feel like someone needs to rewrite Stallman's missives to eliminate the term redefinition and the connotation management. His usage of these rhetorical techniques is far too ham-handed to be persuasive to those who aren't already convinced, even when his message is important.
