As a user, I am generally in favor of Apple requiring the option to purchase items and subscriptions through the App Store. I would never subscribe to, for example, HBO NOW if I thought I’d have to go through HBO (owned by AT&T) in order to unsubscribe. I want the guarantee of easy cancellation.
I am also fine with Apple collecting a modest fee for providing that service. That fee should probably be somewhere in the 2-3% range. Demanding what amounts to a 30% “introducer fee” is beyond absurd.
I also do not approve of how inconsistently Apple enforces their own rules.