This has nothing really to do with the rights and wrongs of the Hong Kong issue. The NBA has thrown its weight around for years on subjects having nothing to do with basketball, from bathroom debates to slandering the President of their own country (something they would never dare to do with China). So there is a certain satisfaction in seeing them on their knees in front of their masters sucking Chinese dick.
Is saying something about the President now automatically slander? This is the U.S after all. Sorry if you don't like the First Amendment but it comes before the 2d Amendment you like to refer to so it is just as valid.
The comments of LeBron and others, like Steve Kerr and Greg Popovich, went beyond policy differences and were direct personal attacks on Trump. Of course they have the legal right to do it, but the obvious point is they're too cowardly to do that with China, or perhaps they're ok with organ harvesting off political prisoners.