Bookstores that carry porn are porn shops. Apps that carry porn are porn shops, and since the app store has apps that carry porn, the app store is a porn shop.
Can you back that up? Basically nowhere else I'm aware of do we draw that kind of expansive categorization. A gas station isn't a book store if they have one rack of books next to all the snacks. A book store isn't an electronics shop if they have a rack of e-readers.