“Shamate don’t understand the world, nor does the outside world understand shamate,” says director Li Yifan of the subject of his new documentary, a wildly controversial subculture that emerged in China in the late ’00s. His film, We Were Smart (杀马特, 我爱你), gives a rare look into the life and struggles of this group of marginalized, often poor rural youths through their own accounts. It has helped