The only way I can interpret this is that Epic & Friends see Apple has a nice cake which they now want to both have and eat. Given that Apple made the cake and there are other cakes, I think they're being entirely unfair to Apple. If Epic & Friends don't like Apple's rules, they're welcome to get off Apple's platform and focus on other platforms.
I personally don't think it's worth developing for Apple platforms myself, but the argument that developers somehow -have- to develop for Apple platforms is nonsense (the AAA market for games on PC vs Mac makes this obvious). That's only true if you decide you have to reach those users, which is only true if you as the developer decide it's economically worthwhile, in which case you have implicitly agreed that Apple's terms are economically justifiable.