Perhaps the intention of Rob Zombie. There are no black and white, just the flawed vs the worst kind of people.
Draco in Leather Pants: Despite being the most sadistic and reprehensible member of the family by far, and being a rapist to boot, not to mention having personal hygiene that would make a monkey blush, Otis seems to attract a number of female fans.
Ensemble Darkhorse: The Unholy Two seem to have become this, especially among fans who weren't sympathetic to the Fireflys.
Moral Event Horizon: Basically, just about everyone had crossed the line by the end of the movie.
Nightmare Fuel: Everything with Otis, including skinning some guy's face off and forcing his wife to wear it as a mask.
One-Scene Wonder: Robert Trebor as Marty Walker, the aforementioned film scholar.
Rooting for the Empire: Although Rob Zombie said that the movie was intended to have no good guys, some fans felt that Sheriff Wydell's torturing of the Fireflies was morally justifiable and that the Fireflies richly deserved it. Conversely, there have been reports of entire theaters clapping during Wydell's death.