Are you sure it's satire? It's The Guardian, after all. :?
That said, it is funny, but only because of the caricatures it represents. Left-wing Europeans with superiority complexes write to American voters advising them on how to vote. Salon reading Bush-haters lap it up and send back gushing e-mails of thanks. Swing voters with brains say get lost and forget about it whilst those voters without passports engage capslock and scream about how they kicked our assess back in way-back-when. [Please feel free to flame my shocking division of American society.]
I think my reaction would be a raised eyebrow and shake of the head whilst muttering "ah, socialists", or maybe the same as the bloke who said: "We all enjoyed this at work. Cheers."