The abuse he got at Norwich was simply because they are a bunch of utter c***s.
I don’t care what expectations you do or don’t have or how disappointing a player is, you don’t sing songs that are so abusive his own family can’t go to games, especially not when they are basically a kid trying to come through.
There are genuinely not many clubs where they’d consider that an ok thing to do, just because a kid isn’t as good as you’d hoped. It’s not like it’s a “football thing”.