Many poems and such have been written about the American flag. One of the reasons Americans find it as a source of pride is due to how the nation was developed (or perceived as developing).
Americans feel that as a nation we are a melting pot of other nations, coming together as one people. We fought for independence, for the right to govern ourselves. The flag became a source of defiance to the British crown. The nations anthem is written as a tribute to the idea that even under the insistent bombing and attacks, it still flew, never to be brought down in battle as surrender.
The flag represents American strength, American tenacity, American will power. Our devotion to the idea that all nations should have the right to govern themselves (that particular notion could be a lengthy debate and another thread).
So when you see Americans rally about the American flag in times of national sorrow, or flown at half mast. It is done to rally about the sacrifice that was given in the name of a nation, that was once just colonies, and came together, in a union of states. Motivated for a common cause.
Now to the reason someone might burn the flag (other than established disposal/retirement of a flag). When someone burns the American flag, and it doesn't matter what nationality, or nation you are in or from. When you burn the flag, it is to protest the actions of the American government, its actions. To protest the policies that are being set. Burning the flag is as much of a symbol of individuality and freedom as is the flag its self.
As far as the Iwo Jima flag raising. That was as much of a symbol of prevailing over the enemy, as much as is the rally around the flag found in the rubble of the towers. In the face of the worst losses, the flag will remain. Never to be taken down, never to be surrendered.
**This was just an opinionated rambling, the facts may be different, but the perception is still the same**
Perhaps burning a bra that looked like an American flag, while it was on Asia. Now that would be something I could enjoy watching.
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