...because you always have to look like you're having one. And Justin does. Sure his party sometimes looks like its going to become an all night kegger, but he keeps advisers around to make sure that doesn't happen. Never underestimate how far an outgoing, enthusiastic personality can take you in politics.
As for Forum, does it even matter anymore if their polls are crap, since crappy polls are all that's on offer these days? They're basically treating their surveys as adverts for the company, and its working. Read the papers these days and you'd think they're the only polling firm in Canada.