Similar to Girl-Show Ghetto
but with racial minorities instead of females. This is the idea that fiction centered on a person of color (POC) cannot entertain or otherwise appeal to people outside of that race. Marketers might fear that a work starring a POC will be focused on issues of race and culture, driving away audiences who are not interested in such movies. They might also fear that white audiences won't be able to relate to a POC in the lead.
The result of this belief is that works starring people of color are rare compared to works starring white people. If a work of fiction wishes to deal with issues of race, it will likely star a white person with POC's as supporting actors. See Mighty Whitey
, White Man's Burden
, and White Male Lead