Christian missionaries progressing through heathen Africa were affronted by the fetishes of the natives; these could be anything from a rock to a carved idol, depending on the sophistication of the tribe. Before long, throwing down native fetishes became something of a triumph; you see, when you ascribe inherent value or powers to an inanimate object, you also invite others to demonstrate that their power is greater, by destroying the object.
This is why the bible and the gospels are just books recording the words of God. You can't destroy the words of God by burning (or even writing naughty words in) the book in which they're written - once spoken, they exist always, and can't be undone. Moslems, like other heathen people, have made the mistake of ascribing inherent value or power to a the Koran, effectively making it a fetish no different from a carved idol or a lump of heathen clay.
We should hardly be surprised therefore that folk around the world are quietly burning Korans and not being struck down by God's wrath. It's just a book. But if you believe that the prophet's power is destroyed a little bit every time someone burns a Koran, it won't be long before tens of thousands of the things are being quietly barbecued. You see, you don't have to publicise it - if you believe it's a fetish then the power is destroyed whether it's burned in private or in public. What Moslems should be worried about is we kuffirs buying copies in the first place; perhaps they should ban printed copies themselves altogether, and rely solely on the rote-learning by Imams of the words, it being somewhat harder for haters to burn Imams than Korans.
Or perhaps Moslems should get wise and recognise that the Koran is just a book, not a fetish; that it hasn't in itself got any supernatural power. Then those who seek to stir up Moslem ire by burning it will be disarmed, disempowered. By the same token the Americans should admit that the stars and stripes isn't a fetish either, just a flag; and the USA isn't weakened every time someone soaks one in lighter fluid and ignites it.
C'mon. We're wiser than this, aren't we?