Alternate Character Interpretation: The novel often hints that Julian was in on some of the clique's goings-on; he only flees when they're about to be caught. Although unlikely, early portions of the story are written in such a way as to hint that he actively had something to do with it. Maybe not, but he does seem a little too perceptive to just turn a blind eye to the fact that something is going on with his students.
Is Bunny genuinely bigoted, or just trying to get a rise out of the rest of the clique? And do they dislike him because he's prejudiced or simply because the way he expresses it is too barbaric and gauche? The world may never know.