You missed the point completely.
Apple >forbids< any browser engine on iOS other than their own Safari. So you can't just install Chrome on iOS, because when you do you get Safari instead.
I would not care how Apple cripples their own web browser if they didn't force other browsers on iOS to use their browser engine. They are forcing me to write a native app instead of just tell my customers to install Chrome to have access to the APIs my product needs (web bluetooth).
I am not an iOS app developer, I'm a web developer. I don't have the resources to support that kind of code when I already have a perfectly working web app on the competing platform. I also do not plan to sell anything through my webapp, which is why Apple wants to force developers to create a native app, where they can collect 30% (or whatever % it is now) of anything sold through the app.
It doesn't matter what the standards are or aren't. Apple are just being greedy assholes and what they are doing is absolutely worse than what Microsoft did to get sued in an antitrust case when they simply bundled IE in Windows.
And to make it worse, Apple is on the board that decides what standards get into W3C, so they are blocking useful APIs based on their own greed.
This is part of the reason Apple is currently being sued by the DOJ
https://www.justice.gov/archives/opa/media/1344546/dl?inline