This implies that a riot was the intended goal of the protestors. I wasn't there, so I don't know for sure, but I can't imagine militarized police showing up gave the protestors warm and fuzzy feelings. The implied threat of violence amps up adrenaline, and it only takes one person doing something dumb for the police to violently swoop in and for everything to fall apart.
At the very least, there should be a parity in force used. The current police strategy seems to be overwhelming force, which is both not working, and a moral failure in my opinion.