11.1 Apps that unlock or enable additional features or functionality with mechanisms other than the App Store will be rejected

My apps update (the 3rd one) has been rejected and given the reason above, weird cos it has been on sale with same features in last 2 versions. (updates just tweaked some fonts and basic imagery).

In my app the user has to enter a "special name" in the setting to unlock its entire contents. if another name is entered it is just a basic link to some wiki info. I had to do this as the content may be confidential and should only be viewed by those with the "special name".

My question and sorry I didn't just get to the point earlier is, If apple rejects on the grounds above why is there a Facebook app on the store? don't you need to enter a log in to unlock full features of that app? Must be favouritism of the bigger boys.