With their new single, the supergroup continues a playful assault on youth unemployment, career pressure, and social inequality — Toward the end of the second verse in “Dope,” the 2015 rap-dance single that helped catapult South Korean group BTS to pop stardom, singer RM declares furiously: “잠든 청춘을 깨워 go.” Translation: “Wake up the sleeping youth, go!” Since their debut in 2013, BTS has progressed to become South Korea’s…