You have a right to use it as firewood, if you wish. I would be enraged watching someone burn the flag, because I love my country. However, I love my country because we are free to express ourselves and live our lives as we wish.
The sad thing is that the flag doesn't just symbolize the present government and whatever it's doing that some might disagree with; it symbolizes our ideals and those who have sacrificed for our ideals. It's an insult to those who have fought and died for it even before we had a Constitution.
The Constitution guarantees us the freedom of speech, but it's not an unlimited freedom. A ban on inappropriate flag-burning would not prevent someone from protesting against the government in a vast array of other ways.