As usual there are many opinions about flag burning itself. I even read one suggestion that it was Bush/Cheney who wanted it made into a law. The question of flag burning has been around for many years. Back during the 1960's people were arrested for flag burning during the Viet Nam protests. One young man (I don't remember where) was arrested for using the flag as a patch on the seat of his pants.

The question asked was whether it should be made constitutionaly illegal. Thomas Mann once said "The government that govers best, governs least." I do not care to smoke and I really don't care if others get to smoke in public, but should it be illegal to smoke? It's an invasion of my privacy to make it illegal.
The constitution should not be changed whenever it allows something that someone just does't like.
A flag that is no longer to be used as a symbol of the country must be disposed of by burning. When someone burns it, it's no longer in the hands of someone who shouldn't have had it.