Reading through those quotes (a tortuous process) I'd say that the majority seem to be saying that the boo's were aimed at the coach for subbing him (?) in the last minute when I think he's come on as a sub himself?
They don't seem that impressed with him that said but they do seem happy with Barker.
I think there was booing as he was subbed on, after he put in a bad display after Eindhoven the week before. There's a debate as to whether it was aimed at ASB or the coach's decision but either way it's a tough experience for him.
The consensus seems to be that he played well in the first few games but has rapidly deteriorated and shouldn't be anywhere near the first team. Shame.