I may offend some people for saying this, but I honestly can't see what's the big deal with flag burning.
I doubt the flag means the same thing to any two Americans; one might find it sacred and another garbage, and because this is America that ought to be accepted.
I personally have no desire to damage a flag, but I think other people should have the right to fire one up if that's really the statement they want to make (and it's their personal property). It doesn't actually hurt anyone.
Also... the USA has spent a good deal of time shitting all over other people's sacred things/beliefs/symbols, and our flag is not especially precious. It seems kind of silly that it's okay to put a flag on a t-shirt or lunchbox or sneakers, but if it's nylon and belongs on a flagpole then suddenly it's a big deal!