Well, you are actually wrong on this one. As part of "agreement" with British, HK does retain some sort of freedom of speech and so publicly criticizing china, communist, their leaders.....etc are legal in HK. I am from HK so I know it is legal.
Of coz china is pissed but until the law has changed, those china censorship law doesn't applies in HK. And from TV, movies to printed matter, this sort of "self censorship" usually don't end well in HK or TW market. If they worry about "those messages leaking into china", they are better off IP banned player from China to login, china players have their own version.