Apple’s entire statement is below.
Our license to include the YouTube app in iOS has ended, customers can use YouTube in the Safari browser and Google is working on a new YouTube app to be on the App Store.
It is unknown whether this is due to Apple’s continued ‘Google hate’, or if Google decided they wanted to monetize iOS users and refused to renew the license.
Regardless of the reasoning for the removal, the outcome is definitely anti-consumer: Google’s track record with native iOS apps isn’t good.
Plus, it’ll be rammed to the brim with adverts and have a gazillion links to Google+ scattered throughout.