White people have been playing people from other races since the early history of cinema, but given how very Japanese the Dragonball Z series is - and how its Western fanbase is pretty diminutive by comparison - it felt particularly crass that the protagonist in the live-action Hollywood adaptation was played by the very white up and comer, Justin Chatwin. It's a common tactic for Hollywood filmmakers these days (see: Jake Gyllenhaal in Prince of Persia and everyone in The Last Airbender), and such ethnic cleansing only seeks to enforce stereotypes that the core audience of popular Western cinema won't go see a film with a racially diverse cast, specifically a non-white protagonist. It's really down to Hollywood's cynicism of all things, a lack of faith in audiences. Needless to say, while Dragonball: Evolution was an unsurprisingly dire film - given that if they can't get the casting right, why should we trust them to do anything else justice? - there was a huge uproar from both fans and the film community in general over what was perceived as ethnic cleansing for the sake of a buck. If anything, this controversy probably gave the film a bit more publicity, which it was sorely in need of...