Here in Canada, you can wear a mask at a protest.
The right to peacefully protest is conditional on peaceful. Soon as it's not peaceful, it's not a protest anymore and we have criminalized wearing a mask during a unpeaceful demonstration.
But these limits on rights and freedoms has opened up ways to end peaceful protests.
Counter protesters can join the protest, become violent toward other protesters and get the whole protest shutdown.
You might consider, what if the protest is over the top non-violent. Bouncy castles and hot tubs? The government unconstitutionally crushes the protest.
You end up in our current situation where the right to protest essentially doesnt exist in Canada anymore.
Beware USA, you dont want to go down this road.
I can't grant legitimacy to a government that criminalizes the public wearing masks to protect their identity during a protest, yet allows their agents to wear masks, not wear badges or uniforms, or present warrants when kidnapping persons off the street - and loading them into unmarked vehicles. No legitimate government of the people, by the people, and for the people does these things.