We need to give kudos when they are due.
Apple's Private Cloud Compute should have won some kind of Nobel Privacy Prize, which for some reason does not yet exist.
There's obviously no real technical limitation since if you live in the EU you can sideload an alternative browser in theory (though apple has made it unrealistic in practice since they're ignoring the spirit of the law and instead doing their darndest to resist giving users even a whit of freedom).
And Firefox is in the iOS App Store. I know what you meant to say, and that it’s not the same as Firefox on Android, but it’s wrong to say you’re not allowed to install Firefox.
In this day and age, privacy is luxury, so that's what they sell.
I don't think there are any ethical motivations for them (or any other large corporation - none of them have morals so they cannot act morally). It's just that there's a market niche, so it will be filled by someone.
Only pointing this out because I love Apple's privacy story and don't want your reply to be misconstrued as sarcasm, and thus the reason why it enjoys a singular exemption is because its ineffective.