Peaceful protests are a fundemental facet of a free society and a good thing. Violent protests are an illegal act at which point the protestors become criminals.
It is not hard to disperse a riot if you have the will for it. A small team of snipers can do it with ease.
1. When a riot starts announce it will be met with force perhaps deadly if rioters do not disperse. Announce that looting will be meet with immediate deadly force.
2. First riot, take a leg off with a 300 win mag
3. Second riot center of mass shots.
4. Riots are over.
They couldn’t even do that 50 years ago, what makes you think they could pull it off now? The lawsuits would be unbelievable.
I understand your premise, but I believe you left out “chain gun”.
/sarc