The article states that Apple is extorting users. Is Apple forcing anybody to use their services?
If by anybody you include their own customers... Yes. The case here is driven mostly by Spotify who claim (my paraphrasing) they cannot benefit Apple customers equaly because of Apple restrictive practices and fee model. You may not have purchased a Apple device with intention to use with Spotify, but others may. (Now extrapolate the Spotify story to any appmaker who wish to sell to Apple customers)
The better question is why hasn’t Spotify made a decent watch app that can stream directly to it and download music for off line use? Apple added the ability last year.
How much of a cut does Spotify take from musicians to be on its platform?