Protest is never peaceful, if it is you're doing it wrong. It should be non-violent and as respectful as possible but it needs to be disruptive and you can't be peacefully disruptive

In the USA its because they use facial recognition and then decide to harass you for the next decade over every small infraction they can.

Because nobody in a position of power would ever abuse that power! /s

There have been events where nazis show up to counter protest and film/photograph you to then share among themselves so they can attack you later.

Masks are no indicator of criminality. The idea that bad protesters wear masks is complete horseshit. It serves to divide movements and prevent momentum from being gained. It seeks to dissolve solidarity that couls have been gained at the protests.

Masks allow peaceful protests to remain peaceful if they prevent the violence of the justice system. Sometimes protesters and organizers are simply arrested and thrown in jail for a bit, sometimes even given nonsense charges, which is something that happens to organizers and some protesters in my area.

As well as that, masks can simply be good secops in some counter-protests such as protesting against fascist marches, gatherings, etc. If I’m showing up to show nazis or boogaloos or proud boys that they are unwelcome, the last thing I want is a violent right wing extremist group to try and doxx me. If I’m escorting people to a drag-queen story hour, I don’t want fascists to doxx me.

It’s also smart in some areas, such as Harvard’s campus where organizers are constantly doxxed and accused of antisemitism even though they are not.

Finally, what if the government makes your particular movement illegal? What if they start throwing the book people, accusing everyone involved(or at least the ones they can catch) of domestic terrorism? Wearing a mask will make it a lot easier for you to maintain your freedom when faced with the tyrrany of the state.

Also, masks look cool, and that’s a pretty good reason imo.

Because a nasty disease spread mostly by sneezing and coughing is going around.

Protest is not meant to be peaceful. You're thinking of a demonstration

"Peaceful protest" is the ideal they push because it doesn't work. If it worked it wouldn't be praised. They don't want change.

Protests only work because they carry an unstated show of force.