Going back to that Observer guy,i'm pretty sure he's in some way biased either for United or against Arsenal.
I mean where he says United's fans have been in a class of their own this season.

Portsmouth are the only club you could say that about.I've admitted that most Leicester fans who go to games are poor (though have improved towards the end of the season) yet when we played at Old Trafford it wasn't until we started singing "Champions League,your having a laugh" that the United fans chanted at all.The commentator even said that the United fans only really get behind the team when they're having a period of pressure or something,and that to me is not the sign of fans "in a class of their own" for "wit,invention and style".