the people who belong to Wikipedia have too much time on their hands
The song is most closely a Polka, and was also featured on South Park: Bigger, Longer, and Uncut (listed in the credits as "Kyle's Mom is a Bitch"). Although many believe that the song, as the title suggests, is written in D-minor, it is not; the song is clearly in a major key: it starts in C-major but modulates up a semitone each verse (so the whole song isn't actually in any single key at all).