The Chinese government asked the N.B.A. to fire a team executive who posted on social media in support of pro-democracy protesters in Hong Kong, the league’s commissioner, Adam Silver, said on Thursday in his first public appearance in the United States since returning from a contentious trip to Asia. “We said there’s no chance that’s happening,” Silver said. “There’s no chance we’ll even discipline him.” The executive, Daryl Morey, the general manager of the Houston Rockets, set off the international firestorm with a Twitter post using a slogan used by the protesters in Hong Kong, just as the league was...