TOKYO — NBA Commissioner Adam Silver said the league is not apologizing for Houston Rockets general manager Daryl Morey’s since-deleted tweet showing support for anti-government protesters in Hong Kong, even after China’s state broadcaster canceled plans to show a pair of preseason games in that country later this week. Silver, speaking Tuesday at a news conference in Tokyo before a preseason game between the Rockets and NBA champion Toronto Raptors, went as far as to say that he and the league are “apologetic” that so many Chinese officials and fans were upset by Morey’s tweet and comments that followed — but insisted that Morey has the right to freedom of expression. “Daryl Morey, as general manager of the Houston Rockets, enjoys that right as one of our employees,” Silver said.