The ambitious and hard-hitting documentary "Blacking Up: Hip-Hop's Remix of Race and Identity" looks at the popularity of hip-hop among America's white youth. It asks whether white identification is rooted in admiration and a desire to transcend race or if it is merely a new chapter in the long continuum of stereotyping, mimicry and cultural appropriation? Does it reflect a new face of racial understanding in white America or does it reinforce an...