GOYANG, Gyeonggi Province -- When Netflix’s documentary “BTS: The Return” premiered on March 27, one scene stood out for its tension: Bang Si-hyuk, Hybe chairman, and the members of BTS sat around a table debating whether to incorporate “Arirang,” a traditional Korean folk song, into their new hip-hop track “Body to Body.” Some members voiced concern about foregrounding such a weighty cultural symbol. Bang argued that in a stadium of 60,000 to 70,000 people — with more than half likely to be int