I started writing in response to one commenter but after reading all the comments here, I think many people are unaware of what is going on with Hong Kong and China so the following is my recap of what I have knowledge of up until now. Check the points out for yourself on net.
The protests were peaceful until the police started roughing up protesters and then using infiltrating officers disquised as protesters. And then most recently police have been firing live rounds at protesters, mainly at lower parts of the body. You can track the escalation of these protests as moving from peaceful to violent as a result of actions by both parties but the provoking I think has mainly come from police.
It is a clear example of Chinese government control being exerted upon Hong Kong to bring them into line with procedures within mainland China. Even though the rule of law of Hong Kong was suppossed to be respected until i think 2047?
This same type of unrest goes on inside China on a regular basis. I have read different people suggesting that anywhere between 30 and 70 % of Chinese military manpower goes into policing the people and suppressing unrest. And some people really want to live under this kind of system.
Next time you get to talk with a mainland Chinese person, ask them about the Tianamen Square Massacre. If you dont already know the likely response it's worth the experience for your understanding of what it is living under Communism.