Freedom of speech does not give the right to shout fire in a crowded theatre.
Now people have died, and some of the the blood must be on the cartoonist and the editors hands. If they had not drawn it and published it, this would not have happened.
There was one guy who made a film exposing violence against women, and he was murdered. I suspect, given the way things are going, a similar fate will await the original cartoonist and editor.
It seems you insult Islam at your own peril
BTW some moderate Islamic leaders have condemmed the extremist position