I don’t think that is a from western stereotype, more like a from Chinese one, so calling it “Chinese man” might not translate very well, bumpkin thug would be more appropriate.

He means the guy with a hammer looks like a Hong Kong-er's stereotype of a mainlander.

Yes, I would agree with that.

Because this is... vintage Chinese-style painting. Everyone will appear Chinese-like.

Ignoring the fact that 95% of Hong Kong people are ethnically Chinese...

no, not ignoring it.

Its a deliberate racial characterization in an unfavorable style, despite the fact they're either the same racially or very very similar.

Not saying I like or agree with it, just that its socially interesting.

The second week of the protests involved them hunting down middle aged women who had the temerity to dance in a public park, because said middle aged women were mainland Chinese. This is a localist, nativist protest through and through.

They were softcore sex workers soliciting in the middle of public parks. It's nothing to do with their country of origin.

Were they convicted in a court of law? Where's the legally binding proof?

It's not strictly illegal but it's antisocial behaviour and the government didn't do anything when local residents raised their concerns.

This is a great example of protest art as propaganda.

This piece actually refers to a specific incident where the protestors attacked uncooperative bystanders (presumably fellow HK'ers) on a train at Prince Edward Station, one of whom used a hammer to defend himself:

https://www.youtube.com/watch?v=7IpfKRRbiEQ

Later the police were called by the subway authorities, and went ahead to arrest the now cowed protestors:

https://www.youtube.com/watch?v=c-wKmycZ_DA

The news only reported on the second video. You can also see how "Resist Girl" manages to turn reality into a completely distorted narrative.