RTHK, a government mouthpiece, frequently attacked then chief executive Tung CW. HK government criticized RTHK, but majority of HKers supported RTHK's right of saying something unpleasant to the government.
in NFZM's case, it's irrevalent to focus on NFZM being mouthpiece of GD government. Under mainland law, wang yang has the power to stop unpleasant voices from all GD news media, whether mouthpiece or not.
Unless NFZM directly attacks government, Wang Yang should not intervene.