Not the parent but the article says: "The most important reason... We cannot be at the mercy of a third party deciding if and when they will make our enhancemen

Not the parent but the article says: "The most important reason... We cannot be at the mercy of a third party deciding if and when they will make our enhancements available to our developers. becomes even worse if the third party is supplying a cross platform development tool. The third party may not adopt enhancements from one platform unless they are available on all of their supported platforms. Hence developers only have access to the lowest common denominator set of features." Suggesting that the primary reason for the clause is that it will prevent third party apps effectively blocking enhancements made the the development environment; if you are using your own tools this isn't an issue. Not sure I agree that this means apple will be happy with developers using tools outside Objective C, but it certainly could suggest it.