The purpose of the application description is to describe the features of the application. If your application has Dropbox support then I think you'd agree it's perfectly reasonable to mention Dropbox in your app description. The Pebble is an iOS accessory. It's equally reasonable to describe Pebble support as a feature. This goes beyond simply not mentioning competitors; Apple is preventing developers from describing features of their iOS app. It might be the same rule, but it's being used quite differently and worryingly.

Some apps only exist as companion apps for the Pebble, what are they going to put in their description?