Earlier quoted context omitted.
> It's not expecting to be able to turn it into a business, or a popular app, that wouldn't quickly be shut down. That's just common sense. When I noticed that there is 2 dollar subscription required to use this app, then all my blame from Apple went to these developers. You can't really expect to do business with other company's service's without asking permission or cooperating. Especially, if the required interfac…
It's called a "phone". It works with the "phone network", AT&T communicates with Verizon. They each fund themselves and are interoperable.
iMessage is like Discord. It is messaging service tied to specific backend, and also devices in this case.
What if I reverse-engineer Discord, make a commercial application which uses their non-public backend (not with webview) and never tell anything for Discord? Should the "phone" argument hold in this case?
Discord is not the best example, because it 'allows' third-party level clients on some level, but above should not be the case.