[kunagi7]

Big demonstrations attract all the... Let's call them "different thinking people" around them. Even if demonstrations were done in closed spaces with proper access control some of them would enter anyway.

Communists, Nazis, Confederates, "professional" looters, anarchists, weird conspiracies like the birds are drones, the earth/Finland/New Zealand don't exist, the list could go on for hours... Grab a photo at the correct time and bang, you have successfully "destroyed" or defaced a movement.