The problem with fanatics is often that they don't really understand what they're making a fuss about. While every Muslim is supposed to have a copy of Koran, I don't think that those fanatics actually read and understood it.
This isn't exclusive to Islam, anyway. Compare the actions of Christian fanatics to actual teachings of Jesus Christ. It's obvious that those people either didn't read or understood the Bible.
TBH, Buddhism (and perhaps Hinduism) is the only big religion I know of that didn't suffer from this.
Also, America happens to be a country with a relatively reasonable approach to religion, so it's a bad example for comparisons. Burning a Bible in, say, Poland would have a similar effect to burning a Koran in Iraq, minus the killings (though, considering the recent events, who knows...), and that's mostly because Polish civilians don't usually have weapons (getting a permit is a bureaucracy-laden obstacle course, like most things in there).