What say I go to Alabama, defecate on a bible, wrap it in the US flag and burn the bundle. That's free speech isn't it?
No, it's me being an offensive dick for the sake of it.
Actually, it depends. If you did it just to be an offensive dick that would be one thing. But suppose the US government had done something to you that, it could fairly be said, ruined your life; and suppose you had written about it, blogged about it, contacted the press, etc. etc. and had failed to get anyone to pay attention to you. (I am certain there have been a few people who have been in such a situation.) Since you mention the Bible, let's suppose that whatever was done to you had some connection to Christianity and the efforts some have made to establish it as the state religion of Alabama. I don't think that stretches the imagination much at all.
Given all that, maybe in your frustration you might have reached a point where the only mode of expression you felt was left to you, that would make the point you were validly trying to make, was to defecate on a Bible, wrap it in the American flag and burn them. In that case I would support you in doing so. Once you got everyone's attention, maybe you could then make your point in a more conventional manner.
Perhaps not everyone who would do such a thing has such a good reason. But it's not up to the law to evaluate their reason. The guarantee of freedom of speech means that you can do that if you want to; and then it's up to everyone else to form an opinion about your motives. If we outlaw any form of expression at all, we eliminate the valid uses of that expression, rare though they may be, along with the invalid ones.
So for those of us who believe in freedom, being told that drawing images of Muhammed is forbidden is itself offensive. Worse, going along with that is dangerous -- once one form of expression is outlawed, it gets easier to outlaw the next one. There is a real clash of belief systems here, and I think it is critical that we make it clear that we will not be intimidated into outlawing any speech at all. (The line here is not really between Americans and Muslims; indeed, a sizable minority of Americans would love to have state-enforced censorship of various kinds -- witness, as just one example, the periodic agitation by some for a Constitutional Amendment to outlaw burning of the US flag.)
The original motivation for the prohibition, in Islam, against images of the Prophet (or anyone else) was to discourage idolatry. I think it is fair game to show people that it has failed to do that: that Muhammed is as much an idol as Jesus. The violence of the reaction to these drawings only proves the point.