I think your missing the vital point, forum members post in that moment. We have 3 periods, members comment each period. We can be absolute shite one period, then amazing the next and shite or amazing in the 3rd. So you can call a team "carp/rubbish" in that period, it's fair comment i think.
Also you can be shite all game and still win, it just means the opponents were even worse or we were lucky.