I agree that's a valid reason for developers to follow it, but that's not a valid reason for the EU to require it. Just because a law exists doesn't make it correct, useful, or a good idea. Pick any year in recorded history and you can find a bad law on the books.
Yep, and the EU's choice in this instance is going to lead to some developers pulling their apps out of the store in the EU, or choosing not to release their app in the EU in the first place. Which isn't good for those developers, EU users, Apple, or those who like me who aren't in the EU but like the idea of hobbyist/indie developers being able to sell apps. Yay. Everyone loses!