Epic also doesn't want to be Apple's customer. No one would describe the relationship between Microsoft and Epic as "Epic being Microsoft's customer" because they distribute the Epic Games Store and Fortnite on Windows (Xbox console distribution notwithstanding; there it is more of a customer relationship).

Apple forces everyone who wants access to 50% of the mobile computing market into a customer-oriented relationship, and then complains when not everyone Thinks The Same as they do. Its disgusting behavior.