Few issues with the straightforward narrative you present.
Cops will slowly corral protestors as curfew draws near by setting up blockades or raising drawbridges. Peaceful protestors want to go home but can't. They're confused, and then curfew hits and police begin loading them into wagons. It's not as simple as get home by curfew.
Cops will infiltrate and instigate protests using a variety of tactics, the goal being to escalate tension, and justify the amount of force the cops wish to use.
Similar to your stated preference, they can't wait to be able to justify beating citizens with an overwhelming show of force. It's the fastest way back to status quo. A status quo you admit is broken, but worth using violence to return to. There's a catch-22 in your reasoning here you might be able to poke at.
Body cams and other forms of accountability do not work because the disciplinary board is not independent and not impartial.
Perhaps our countries aren't so different.