I agree that burning the U.S. flag is a constitutionally protected form of free speech. That said, I don't care what your "cause" is. If you burn the flag, you're lower than whale **** in my eyes.
Would I assault you for it? No. I'd consider you to be an unstable person who'd have no compunction about assaulting someone who disagreed with you. Would I use my own free speech to the point that you might assault me, thereby causing me to defend myself from your criminal assault? Well, that would be my right now wouldn't it?
I'm sure all of you who disagree with assaulting someone who is burning the flag would support my right of free speech in this manner, correct?
I like it. So could this be a possible scenario?
Me: "Hey, WTF are you gonna do with that flag?"
Scumbag: "Imma burn it!"
Me: "Please don't, okay?"
Scumbag: "Burn baby burn!"
Me: "Oh no! I consider you unstable and feel threatened with grievous bodily harm, or even death!"
...The End.