@Brandon9000,
The NYC protesters have been mostly peaceful. The The police for the most part have been well behaved. There are always bad folks in any group and the larger the group, the more likely there'll be some incidents.
In some cases, the looting and violence and overall destruction was initiated by "outsiders" . Outsiders might be locals from the 5 boroughs or from outside of the metro area.
Some came with law breaking in mind. They were stopped along the way to wherever and tools of destruction were in their possession. Things such as crowbars which were used to pry the plywood off of stores which had been shut down back in March when things closed down.
Other hooligans managed to escape detection before they began vandalizing. Some escaped again. it was shown that a number of Citibikes were taken out (legally) and used as escape methods. Scooters of the 2 wheel non-motorized as well. These were not protesters. These were scuzzy, scummy cretins. Hellbent on making the protesters look bad and thieving the night away at high end shops.