First of all, there isn't much art going on in popular film, just a lot of marketers and accountants concerned with demographics and sales projections. Considering that, it makes perfect sense that most film and television in the United States caters to a white audience. That's just how business works.

Second, while I think true art is not well represented in American film, there is absolutely white art, and white culture specific art is by no means the standard. Some of Tarantino's films have themes of whiteness in America. Paul Thomas Anderson has films that could be considered as white art, as they deal with the aspects of white American culture (Boogie Nights, Magnolia, The Master). The themes some of the real white artists in America are dealing with are not really present in popular American cinema targeted at white pop-culture.

In fact, most popular American cinema is fairly culture non-specific. You could trade out a lot of the white characters or non-white characters for people of any race. You still need an actor that will draw a demographic, if you want that demographic. I'm not quite sure what the complaint is about that. Are people angry that most whites don't want to watch culture specific films when those films relate to the popular culture of the target demographic? That's like saying it's a shame more black people didn't like Clueless, or Clerks 2, or that they should for some reason be into Asian popular television or film. It's really difficult to get into another culture's pop-culture productions. That's just a fact. It's especially noticeable now, when the internet and streaming video has made access to the pop-cultural output of other cultures so accessible. A lot of it starts to look a little silly, because it is. It's all the little silly things a group of people does that makes that group distinguishable. That's why, while I understand them, I just don't like watching white American pop-cultural output, or black American pop-cultural output, or really any pop-culture specific output, because the pop of it makes it unbearable.

All that said, I love seeing new artists take the stage, whether white, black, Jewish, European, Asian, male, female, whatever. I like to see people avoid the low-hanging fruit of the dollar provided by targeting a popular culture. And there are plenty of black American filmmakers making great art films that do not target a specific popular culture. A quick google search should prove that. Also, if you weren't paying attention when some of those movies came around, well that's not really an issue with art as it relates to race, that's an issue with people not going to watch movies that might make them think.