I agree that the UI is obtuse, but... this icon and tooltip are in exactly the same place that the revolt icon and tooltip have been since Civ V was originally released four years ago.
That may very well be the case, but as others and Firaxis have stressed, CBE is NOT Civ 5. It's an entirely different game and there will undoubtedly be thousands of customers that never played Civ 5. As such, knowing Civ 5 inside and out should NOT be a prerequisite. That means that things like this should be explained
somewhere. And since the game manual tells the player to just jump in and play the tutorial in order to learn the game, it should have been mentioned there. Which it isn't, along with a whole bunch of stuff that players really could benefit from knowing, but never gets mentioned in the manual or in the Civilopedia.