As of the latest Apple TV software update, YouTube is no longer showing up on the home screen, apparently replaced by Vimeo (which I like, but which has a very limited video selection). Is there any way to get YouTube back on the Apple TV home screen?
You might have turned off YouTube under Settings -> General -> Privacy. Check there, and then toggle it back to SHOW. If this was the problem, please "Accept" the answer.
I don't think Apple has removed YouTube. Try logging out of your iTunes account, then back in.
Which generation Apple TV is this on? YouTube has been removed from all but the 3rd gen hardware as Google retired the API in use as of April 20 2015 (Announcement)
You can't get this YouTube channel back until Google re opens its streaming feed API for older devices. They probably won't until they can rewrite it to incorporate in-stream ads.