Why not? It worked for Stepin Fetchit and Hattie McDaniel (the first black actors to become a millionaire and receive an Oscar, respectively). Carl Weathers's movie career was launched by Rocky, yet he admits the film succeeded in great part by playing on some pretty insidious racial tensions. And that's just scratching the surface of one minority group. Do we need to get into the thousands of actresses who accept roles that are utterly degrading to women, and in all-too-many cases literally whoring themselves out to executives for bigger roles and more exposure? I'm not saying Best considers Jar-Jar a racist character. But it's just naive to think that no one would take a role degrading to their race/gender/orientation/etc. if it would help their career. And TPM was guaranteed to be one of the biggest movies of all time before the cameras even rolled - before Lucas even put pen to paper on the first draft of the script.