From the forum comments, this is new behavior. It seems connected to Apple entering Pebble's space with their new Apple Watch. The existing Terms of Service about competing platforms is now being interpreted to consider Pebble a competing platform. The developer appealed and Apple told them that they specifically can't mention Pebble anywhere in their app description or metadata. Other developers have confirmed that Apple is now forcing them to remove existing screenshots in the App Store that demonstrate a given app's functionality tied to the Pebble.

So, yes, it is Apple being anti-competitive now that they have entered the same space as Pebble. Apple are attempting to kill off Pebble support within the iOS ecosystem. It appears Apple will only allow mentions of Apple Watch within the App Store and in screenshots, no other smart watches going forward.