A film cannot live on celebrity cameos alone. But "Zoolander 2" is certainly going to try. Because cameos are low in calories, and "Zoolander 2" hates calories, because they make you fat, and "Zoolander 2" hates fat because it means you're a terrible person. But not as much as "Zoolander 2" hates male models, who are dumb and useless.