There is a strict line.
Protests get permission, they do it in appropriate places at appropriate times, they don't interfer with everyday people's lives, they don't destroy, loot and burn, they don't attack police or civilians, and essentially protest as is their right but do so without breaking any laws.
Anything beyond that is a riot.
And if politicians won't let allow the police to handle rioters stealing, looting, burning, attacking people and so on then I have no problem with them being shot by the people who are left to deal with rioters.
Protestors are a American privilege it's a solid part of our country, rioting is breaking the law and illegal.