I DO know something about China and Hong Kong, having lived/worked/studied in them, and having half of my family there. And of course, as in any of these things, nuance is the first thing that goes out the window.
First, although Hongkong has been peaceful in the last decades, it has had some pretty severe rioting before, in the 60s and at various other times. But what we see now is a drawn out result of the 1997 hand-over. There are many factors. One is that China (and the colluding business interests) have moved step by step in opposite direction of democracy. Another is more about psychology - Hongkong used to be a star in the region, but it's now in Chinas shadow and more and more dependent on the mainland, even "overrun" in certain ways. So there is a built up frustration in Hongkong around both of these things.
China has not yet brought down the hammer on Hongkong, and they have not removed property rights and the overall freedom. Sadly, these protests are more likely to bring the dictatorship closer. But all revolutions are like that. Almost inevitably they turn violent (on both sides). The government feel the need to push back harder to quell the fire. In any conflict, both sides lose. And yes, almost inevitably
Now, that's the nuance. Then you have the simple fact that China is not a democracy, it's an oppressive surveillance one-party state. All of the democratic world has a certain moral obligation to either attempt to transform or to oppose China. Unfortunately, most have gotten in too deep and have too much to lose on criticising China. Therefore the global response is weak, and large corporations tend to follow the money rather than the principle. This is very sad.