The problem here is that the "escalation" is not against the people threatening lives. It's a blind escalation in the dumbest sense - just making the antagonistic act affect more people instead of the few guilty people more acutely.
Collective action protects those who do use their free speech. If all western newspapers printed the original cartoons threatening all of them would be impossible. If one guy gets killed for making a movie and a hundred directors makes similar films it is now safe to make those movies again. There is no single person to focus the anger on.
Edit: I mean, if they had been asked nicely I would totally agree with you. But it must be made clear that threats are not an appropriate way to deal with religious issues.