There is a moral/philosophical connection to free speech and the app store pseudo-monopolies (code as speech), but it also happens to be very concrete in Apple's case: you literally cannot tell customers through your app what other alternatives might be used to pay you.
(And before someone comments about how this doesn't conflict with the 1st Amendment, you are obviously correct; but free speech is as much a societal value as a legal construct, and is not limited to the Bill of Rights as its sole champion.)
(And before someone comments about how this doesn't conflict with the 1st Amendment, you are obviously correct; but free speech is as much a societal value as a legal construct, and is not limited to the Bill of Rights as its sole champion.)