Why didn't Todd Bridges star in John Hughes' film, "The Breakfast Club?"

Same reason why black characters in movies still suck.

Every movie that features a black character always has to throw in a stereotype of some sort, because the writers, who are mostly white male believe that they have to throw in some sort of black hook to make the character appear black. Its the same reason why the ever so rare asian character always has to speak Japanese, Chinese, Korean or whatever recognizable asian language half of the movie, or eat sushi, bonus points if they know someone in the triads.

So while the white characters are free to be independently minded (unless they're in a mostly minority movie/TV show, then they become the token white guy/girl) black characters and other minorities always has to have to fill some role that is deemed appropriate for a minority character, like a magical negro, wise old black guy, thug, sassy black woman, suave loverman, effeminate gay black guy, jungle savage, etc. Perhaps the worst are the movies where some white character, more often now a woman, goes into some minority neighborhood and teaches the minority kids to read/not use drugs/believe in themselves as though by default.

A recent example of this sort of typecasting is in the movie The Blind Side. Although the movie is based on a true story, it was chosen for release as a movie because it falls within accepted norms for a story like this. Basically in these types of movies the black kid is always a tall muscular fat guy who is uneducated (usually illiterate) and has some sort of family disfunction, in the 80s and 90s it was likely that he would have been a crack baby. Anyway, he usually takes the form of King Kong, especially when he is placed next to the white blond female protagonist, who's job is to save him. This is basically the template for many of the black characters you will see in a major motion picture unless the actors are famous, in which case they'll fall into one of the many roles I stated otherwise. Precious also falls subtlety into this role. although she doesn't have a white heroine, her inspiring friend was altered from the novel format where she was a dark skinned girl with dreads to a light skinned girl.