Quite simply fear is the only thing that would cause such a reaction. They feel that their beliefs are being threatened which would leave an observer wondering how strong those beliefs were in the first place.

Often when someone feels their beliefs are being challenged, they feel that their very identity is being challenged and driven by an excruciating fear of losing this, they will often go into panic mode and will stop at nothing to protect their own identity (ego) and they don't realize that their true identity (higher self) doesn't need protecting. From their current state of awareness, they have to be right at any cost.

Like Michaela says, it's based on fear...and perhaps some powerlessness, depression and insecurity etc (over the 9/11 World Trade Center attacks) thrown in for good measure.

Anger (embodied physically as violence) against someone else or something else (like the Koran) is a way for them to feel better.

If you look at the diagram of the emotional scale below, you can see that Anger / Revenge / Hatred (17, 18, 19 on the scale) are better-feeling emotions than Fear and Insecurity (21, 22 on the scale), so even anger against a book makes them feel better than before...plus there's probably more than a bit of publicity-seeking too :)

For a full explanation of how being angry and vengeful helps people feel better, see Why are people mean to each other?

You're forgetting one thing. Nobody actually burned a Koran.

This is one of the most egregious examples of non-news I have ever seen. Some crackpot in Bumf**k Florida states that he is going to hold a Koran burning party, and it makes international headlines. Then he calls it off because he claims the guy building a mosque at ground zero in Manhattan has promised he will move it,
which is not true.

Are you kidding me?

It's like the press reporting on Paris Hilton stating for the n^th time that "That cocaine in my purse is not mine." WHO CARES?

When Hilary Clinton suggested in a press conference that it might be better if the press just not cover the story, the press corps laughed at her!

The press is a bunch of dickweeds.

Most news on the TV and in the newspapers is negative, sensational news. It's what sells, and it's what gets the people's attention. Always has been that way....... that's why I avoid it! And then you will always have attention-getters and then those who react to everything, protesting in the streets over something across the world that does not even effect them. And on-and-on it goes.

Why do we cry Wolf, when there is no Wolf? Are we looking for attention, or are we looking for fame? Regardless of the reason, one cannot help concluding that this is perhaps, some sort of a conspiracy for the purpose of Media attention, and profit. Maybe as we speak, this Pastor is writing his Book the next Best Seller: The Koran In Flames? Lie! Lies!