2. This link is about what's happening in Hong Kong, not the US, and this sort of what-about-ism isn't informative or helpful.
People are (rightfully) outraged when a protestor dies in Hong Kong, but protestors also die in the US.
For example, the Kent State shootings: https://en.m.wikipedia.org/wiki/Kent_State_shootings
The point is that if you’re demanding a certain standard from China or other countries, you should demand that in the US as well.
I think this kind of what-about-ism by comparing to the US contributes absolutely nothing to the current discussion around police violence in Hong Kong. Unless it's used as an analogy to actually make sense of the situation ("the police are doing what they're doing at Kent State, can we learn something from that which would be applicable in this situation?") it only distracts from the topic at hand rather than actually discussing the morals and context of what's happening in Hong Kong, which is what this link is about.