1) Traditionally the Chinese government largely left the affairs of HK to HKers (in reality just the few families), so there is no reason to step in and be the bad guy right now.

2) This protest/riot is far more complicated than it seems, considering the meeting with the US diplomat as well as the involvement of the boss of next digital. Geopolitics plays a hand here.

3) Protesters should target the ruling families (e.g. the realtors) instead, thus would gain the psychological support of mainlanders. Targeting the tourists doesn't help.

4) Hope nothing really bad happens and everything goes as peacefully as possible.