"'violence' would not do our side any good "
Probably not, but it would do wonders for my heart. And it would even be LEGAL (sort of

)
An ass whooping would be protected under the First amendment as a form of expression, It would not be PREVENTING them from expressing their stupidity in this assinine manner, Not depriving them of life (just some teeth) not depriving them of liberty (unless you hold them up when they want to fall down)Not even preventing them from PURSUEING happiness (it's just harder to catch with those casts)
All in all, probably a $100 fine 1 week in jail suspended and an admonishment to go forth and sin no more, at least not in that county

If they can trample OUR flag why CAN'T we trample their asses ?