I don't think that they are, I think that they are the face that you like to put on the left because you think it works for you.
I play Trivia with "the left" on Wednesdays. They aren't anarchist idiots out there spewing about the evils of capitalism, the fed, jews, and the general injustices of the world. They are neo-quakers, school teachers, a handyman at a senior residence, an antique dealer, a retired director from Nav Air, an accountant at a major Christian organization and his son the aspiring (but unlikely) entertainment lawyer. These people will never vote Republican (except the lawyer son who is a Ronulan), they will go stand on the corner of US 19 and 22 with Stop The War signs, but they will not burn the American flag or hang out in Oakland.
Those people you play trivia with don't end up on the news every night though.
The "face" is the part that gets publicity.
In most sports, cold-cocking an opposing player repeatedly in the face with a series of gigantic Slovakian uppercuts would get you a multi-game suspension without pay.
In hockey, it means you have to sit in the penalty box for five minutes.