So let's see Hollywood makes movies about all of these comic books, video games, cartoons, children's books, fantasy novels, etc and almost all of these films are lily white because the source materials are filled with all white characters. Or if not all the characters are white certainly the most important characters will be white leaving the characters of color to play more token roles. And with the source materials come a sense of familiarity and a sort of expectation that fans (particularly fanboys) want the studios to follow strictly. So any suggestion of a black Superman, a black Captain America, a black James Bond, a black Batman, a black Tarzan are passionately shouted down by these fans. And that is totally acceptable because I too believe in respecting the source material. I go along with the typical white fans' response that if you want a black person to play a major role than pick a black character as a lead for a film. Fine with that too.
Then comes a series of film that stars a black character, a rarity in films. The character is based on a source material, a comic book, in which his race had been established. The first two parts of this series of movies, The Blade franchise, do very well at the box office and almost single handedly kick starts Marvel's recent successful run of movies. So when the third film of Blade comes around what do the writer and director do? They decide to make the third film more about two white characters who were created for the screen. Do you see Hollywood making a third Batman movie focus more on some random black male character? Don't think so. Here was one of the few opportunities for a franchise revolving around a black man and Hollywood still decided to "whiten it up" and make Blade less prominent. Why? Guys like Ryan Reynolds gets COUNTLESS opportunities to play superhero types because 99% of those characters in comics are white men. He didn't need the opportunity to be the star of a movie that was supposed to be about a black guy. Did you ever think about that when you were sitting back and marveling how his presence in Blade 3 made the film watchable?