THR gathered six non-fiction filmmakers -- Ezra Edelman ('O.J.: Made in America'), Werner Herzog ('Into the Inferno,' 'Lo and Behold'), Kirsten Johnson ('Cameraperson'), Josh Kriegman ('Weiner'), Raoul Peck ('I Am Not Your Negro') and Roger Ross Williams ('Life, Animated') -- for a discussion about when to intercede in a scene, how much brutality to reveal on screen and why the diversity issue is "worse" in the doc world.