There is a thread over at the Apple discussions on this that I have been following. Interestingly, there was mention of this and that post has been removed. The terms there do not allow for discussion about Apple's course of action but they seem to allow for second guessing Facebook's actions. Either way nobody there can answer why or how the Facebook feature existed, is mentioned, or the way it is supposed to work.
That's because Apple values privacy; primarily their own, of course!