You break a reasonable law, you should face the consequences.
Burping while the national anthem plays is not a reasonable offense in my world, but damaging private or public property certainly is. Setting rubbish bins or whatever on fire is certainly an offence. Colluding with triads is an offence too.
What worries me, all this violent action may achieve exactly the opposite, public sentiment goes to 'something-needs-to-be-done', and since the HK police does not have the manpower that would mean the PLA, and we know they will not hesitate to kill people if being told so. But maybe this is exactly what they told Carry Lam to do to make 2047 come 28 years earlier.