SINGAPORE—Netflix’s newest high-powered sci-fi drama, “3 Body Problem," is one of the biggest cultural events to come out of China in years. After watching it, many in China say they wish the producers of the show had taken their country out of it entirely. “3 Body Problem" is the long-awaited adaptation of a critically acclaimed series of science-fiction novels by Chinese writer Liu Cixin. The project was helmed by “Game of Thrones" showrunners David Benioff and D.B. Weiss, along with “True Blood" writer Alexander Woo. The show has topped the streaming giant’s U.S. rankings since it was released. For China,...