Even in sheer numbers, if you want to consider these people "Conservatives" I'll play along.
They are going against something specific, Anti-abortion. That can be inspired either religiously or politically (Although I doubt these people show also show up pro-gun rallies, Pro-war rallies, Clinton protests, CAIR protests and break into offices of prominent left-wing politicians) But I'll go along with your mis-understanding and even call them "Conservatives".
Lets compare that number to the number of people that protest the war, threaten to kill bush, mother-fuck everything that the white house does, protest National Conventions, and call for Attorney General's heads on a platter. (These are ALL political maneuvers)
The number of extreme leftists (And violent leftists) are far more than Violent (And remember.. I don't accept that anti-abortion protests are Political in nature) conservatives.
Conservatives protest in the form of votes, legislature and writing. Liberals just scream louder.