The Americans wear their heart on their sleeves much more than the Brits do - plus, if my A level politics memory serves me correctly, the American candidates are allowed to spend as much as they can raise via funds for their election campaigns, whereas our parties are limited by statute as to how much they can spend (this may well have changed, or I may be mistaken - politics lessons seem so long ago now).
Also, we would just look ridiculous partaking in that sort of bruhaha - do you remember New Liars when they won the '97 election when they were signing and dancing to Things Can Only Get Better? It was just pathetic - B.Liar and his scuzzy mates looked like complete prats.