I don't consider protests to be "peaceable assemblies", nor do I consider their activities to fall under the "freedom of expression". They are loud and disorderly and they turn into riots far too easily. They interfere with citizens going about their lawful business. So, yes, when they gather in numbers and start shouting and waving picket signs, I think firehoses and attack dogs are the most appropriate response.
The founding fathers would probably argue against your position...
"The jaws of power are always open to devour, and her arm is always stretched out, if possible, to destroy the freedom of thinking, speaking, and writing."
John Adams
"If ye love wealth greater than liberty, the tranquility of servitude greater than the animating contest for freedom, go home from us in peace. We seek not your counsel, nor your arms. Crouch down and lick the hand that feeds you; and may posterity forget that ye were our countrymen."
Samuel Adams
"Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote!"
Benjamin Franklin
"The Constitution is not an instrument for the government to restrain the people, it is an instrument for the people to restrain the government -- lest it come to dominate our lives and interests."
Patrick Henry
"Those who expect to reap the blessings of freedom, must, like men, undergo the fatigue of supporting it."
Thomas Paine
"It is the duty of the patriot to protect his country from its government."
Thomas Paine
What country can preserve its liberties if its rulers are not warned from time to time that their people preserve the spirit of resistance? - Thomas Jefferson
"Posterity, you will never know how much it cost the present generation to preserve your freedom. I hope you will make good use of it. If you do not, I shall repent in heaven that ever I took half the pains to preserve it." - John Adams