It's probably pointless1 to tell the various empty suit/talking heads this, but May Day is not, in fact, a traditionally observed day in the USA. This is probably because it's the Big Day for commies, anarchists2, and other various insurrectionists.
As for "legitimate" demonstrations, in America these things have "traditionally", so to speak, been very disruptive to those trying to go about their legitimate business. Sometimes they get a permit, but even when they do, they have always wound up doing things like completely shutting down I5 through downtown.
Look, May 1 has only recently become a day that wasn't like any other day in the US; note that, when and where it is observed, it is in favor of things like a universal amnesty for illegal immigrants, socialized health care, declaring the Industrial Revolution hull and void in favor of us all going back to a neolithic lifestyle, as well as a day when organized labor lets it's mask slip so we can see it's fascist, totalitarian, communitarian roots. That's why we celebrate Labor Day in September: the Bad Guys had appropriated May First3...
How any sane human being can still speak of the #Occupy movement as being anything resembling "legitimate", not to mention "peaceful" and/or "law-abiding" is beyond me; we had plenty of examples last year of how commies and anarchists individually were bad enough but when you mix the two only trouble can ensue.
But recognizing that wouldn't support the narrative, would it? So you have to pretend that May Day is a day for lofty observances and high ideals, and pretend to be shocked, shocked!!!, when things go south.
I'm only surprised that you haven't tried to pin this on Tea Party provocateurs...
***1.I originally wrote "needless", on the theory that the newstards were all familiar with the history of the Comintern.
2. Some of my best friends are anarchists. They don't run around smashing other people's property, though.
3. And, sure enough, some useful idiot was blathering about how "If we observed May Day as a Federal Holiday like they do everywhere else this wouldn't be happening..."