> they publish the whole development toolsuite needed for free without obligation
The hardware is not published for free. The minimum entry fee into, say, iOS development is 100$ plus the cost of a Mac Mini.
Blimey apple is so hard onto us poor honest developers. Why don't they give a Mac to every human being so we all got equal opportunities to code?
(That would actually be a great thing to do, but 2020 reminded me hardly that we don't live in a fairytale)
That's not my point. The point is there is no technical reason for requiring a Mac for, say, iOS development. I get that they don't want to straight-up port XCode to Windows or Linux, but nowadays you could run it as a cloud service. The price of admission for something like that would certainly be less than keeping up with Mac hardware. They don't do it because it runs counter to their business model.
So the 100$ annual fee is more like a contribution to be recognized as a professional developer with extended support and services. Heck if you work in a team you don't even need one account per developer.
This somehow guarantees that each account is linked to an identifiable real world entity and that bad actors won't massively create fake account for free to muddy the water around illicit activities.
So by imposing a relatively modest fee they improve both traceability and avoid spamming behavior. This sound like a sensible design.
PS: I'm amazed by how on the same thread people can complain that the 1 million $ threshold for rebate is cruelly low AND that a 100$ entry fee is an unbearable tax. Internet trolling at it's finest!