Being a quarter Canadian (my grandmother on my dad's side), I personally found this song to be extremely hilarious and good-natured. Of course, I am an American, born and raised, and I've heard plenty of jokes on Canadians, but the point is not to be offensive. And besides, if you do make fun of Canadians in any shape or form, they'll thank you and offer you a drink of their beer. They're just a bunch of simple-natured, calm and gentle folk up north that we down here love to poke fun at down here. And they, in turn, have many jokes about Americans. In general, it's just well known that America and Canada are the best of friends, and so talking trash to them is really a playful punch in the shoulder between siblings. Weird Al effectively wrote a masterful piece of music that captures the well-natured jokes made toward Canadians. At the end of the song, it is shown that the narrator actually believes these things, as he calls for America to make a "preemptive strike" against Canadians, but again, from the stance of the satire and comedy, it's still all in good fun.