Today is the anniversary of China as a communist country. The Hong Kong marchers were all wearing black today as a sign of mourning. That is why the kids are dressed in black (so please, no black bloc/antifa comments.)
The police have been particularly aggressive towards protestors and journalists. They deliberately shoot tear gas at journalist "clusters" (presumably to prevent documentation of police actions?) They have shot multiple people with "rubber bullets" and they beat people with batons. The first people to use shields and clubs at the protests? The police.
Besides the state authorized use of violence, there is also the use of non-state assets. The authorities have encouraged the triads to assault protestors. The police stand back and allow this to happen, probably because a picture of civilians beating people is a less polarizing image than police beating protestors.
# the shooting
From the videos it is clear that there was an officer on the ground and he was being assaulted. He is wearing protective equipment. When police beat protestors with batons the protestors do not have the benefit of riot gear.
The officer who shot the 17yr kid should not have had his service weapon drawn, and should not have had his finger on the trigger. When a cop points a gun, finger on trigger, at someone the only party responsible for that shooting is the cop.
The "descent into violence" narrative adopted by the Western media is completely missing the nuance of the protests. Most of the "violence" by protestors is property damage. It is seldom violence against a person.