You're assuming Android apps and iOS apps are the same market. Which they might be if they both ran on both kinds of devices and you could distribute iOS apps via Google Play or Amazon, but that isn't the case.

It's like having a regional monopoly. Even if Google has 80% of the world market, if no one but Apple has a store in California, they have a monopoly in California. If you (or any of your customers) live where they have a monopoly (i.e. have an iOS device) then no other app distributor is reasonably available.

Obviously they could change that by not restricting iOS users from using other app distributors. They separated iOS app distribution into its own market explicitly and on purpose, but that's still what it is. "Windows app distribution" might be its own market but Microsoft has no monopoly on it.

I am assuming that 99% of people on HN with opinions have zero understanding about law and how it applies to each jurisdiction across the globe.

Like your comment proves by the way.

You're implying that it's wrong even though the economics of it are right and the sane legal systems are going look at the economics of it.

I am implying that anyone that is clueless about law has no place calling Apple whatever they feel like, just because it doesn't fit their world view.

You still haven't given any argument for how they don't have a monopoly on iOS app distribution, or why iOS app distribution and Android app distribution should be considered the same market when they don't run on the same devices, the set of customers is effectively 100% non-overlapping, and they can't in any meaningful way be substituted for one another when a developer would still need both to reach the entire "market" if the market was defined to include customers on both platforms.

You don't get to define what is a monopoly to fit your world view.

The market is mobile phone devices and each device owner is free to set their own rules on their devices.

Apple is just a big supermarket chain, and like any supermarket chain gets to choose what comes on the shelves, don't like it? Go to another digital supermarket and get a law book for your jurisdiction.

world wide market share is immaterial as such decisions are not taken at global level. In US it has ~50% market which makes it dominant enough.

Which still might not be enough legal basis, and when it does, it is specific for one country among 195 acknowledged countries.