As a possibly better analogy... Let's say I run a Flea market and also direct sell some items to customers. I charge independent retailers a fee for setting up a booth in my market space and don't excise that same fee from my own booths. Then I go to open a booth in a local mall to help sell some of my directly vendored items and raise an exception all the way to city hall that the mall attempting to charge me for running a booth in their property is impeding the free flow of commerce and hurting the local economy - while I continue to charge booths in my market space for operating.
Except Apple has never made that argument to anyone. They simply added a way to pay for their subscription directly in their app rather than in the Play Store; Something Google allows.
If 7-11 doesn't sell a bible and I want to buy a bible, I go to another store that sells bibles and buy one there. It's not like my house will refuse to allow me to bring a non-7-11 product inside.
If the iOS App Store doesn't sell a particular app, then I have no alternative (aside from "buying a different house", which IMO is unreasonable), because Apple doesn't let non-App-Store apps onto iOS devices.
For an annotated bible application, you would have the option of a web-based application, which has certain trade-offs.
If I want a copy of the King James Bible and 7-11 chooses not to sell that, I have to leave 7-11 and go find another store that does. Yes, that's a barrier I have to go through to get my Bible. Should the government make it 7-11's responsibility to solve that for me?