Huh???? I have no problem with the feds taking pictures of people at these demostrations. They are in a public venue, publicly protesting. They have ABSOLUTELY NO expectation of privacy here. If you don't want your face associated with this activity, don't show up!
I think the police should have multiple video cameras running at every public event. If there are no problems, good. If there are, then it is just like a dashboard camera, good evidence for court.