[mjthompson]

That is not a matter of concern of Apple. This is just one of several examples of Apple forcing behaviour changes outside its own walled garden.

Whether or not it makes business sense to restrict the use of Apple ID elsewhere is a matter properly left to the app developer and not Apple.

I should have added - this is based on my own interpretation of the App Store guidelines. If I'm wrong, I'd like someone to point it out, since I don't want to be spreading misinformation.