Here is my little rant on the issue....
In the US, we don't ascribe any magical properties or even religious properties to our flag. Outside of obvious uses as a government standard, the power of the flag is what the flag represents. Those who died for the flag, didn't literally die for a piece of cloth, they died for the freedoms and liberties that the flag represents. Freedoms which (should) make us a unique nation. Freedom of religion, freedom of speech, freedom from tyranny, putting the rights of the individual above the power of the State. That's what the flag represents.
Some people will abuse those freedoms, but that does not mean those freedoms should be stripped?
Someone abuses the right to own a firearm, an abuse that literally results in the deaths of others. Not just a flag being burned but people dying. Does that mean that we should strip 2nd Amendment rights from everyone because someone abuses the right?
If we ban burning the flag as now a non-protected form of speech, are we not changing the flag's meaning? We now are putting the physical piece of cloth at a higher level than the rights it represents. We are putting the government's power over the individual. The rights and freedoms are now less important than the single object.
But let's go back full circle, because the flag isn't just a symbol of our freedom. As I mentioned before, it is also the government standard. A physical representation in an ancient sense, of the ruling authority. Just like how a flag flies over an embassy to let citizens know this is our sovereign territory or a soldier wears it to show what nation he represents. It is an entirely different meaning than just a representation of our freedoms.
Sometimes the government opposes the freedom the flag represents to us. Long before the history of our country, when citizens stood up to an oppressive government, they tore down her flag and often burned it as a symbol.
It isn't just burning the flag, for many, flying the flag upside-down, as a sign of distress over the government, is just as offensive if the context is not known. Should that disrespecting the flag also be banned in the same manner?
And one more point if I may. What about religious symbols? For many of faith, religion is a higher priority than government. God comes first in their lives, then family, then country/community. If we hold religious symbols on an even higher level than we do national symbols like the flag, should we ban burning those? Should we ban burning of the Bible? How about the Koran?
If we've gotten to the point where the government threatens free citizens with prison or revocation of citizenship for simply burning a flag, ask yourself, what is the government afraid of with the citizens having that freedom?