Unpopular opinion: This was a no brainer. Apple wanted 30% (or was it less for subscriptions?) on any business that used apps, no matter if they used apple infrastructure or not. Just think about it: one company is in practice entitled to 30% of what any other business makes (in any industry)!! Also, I think apple brought this to themselves by picking a fight with Spotify (on Watch support).
For most companies, such a demand would be fine, legally (suicidal, but fine. Companies are free to make stupid decisions)