Boston Celtics games were abruptly taken from the Chinese internet on Thursday after a center for the team, Enes Kanter, said on social networks that the country’s leader, Xi Jinping, was a brutal dictator, citing his government’s repressive policies in Tibet. The incident could lead to new problems for the NBA in China. The league has millions of dedicated fans there, but also just spent two years repairing its image in the country after a Houston Rockets leader tweeted his 2019 support for pro-democracy protesters in Hong Kong. That tweet, from Daryl Morey, who now works for the Philadelphia 76ers,...