It was absolute provocation, there's no disputing that. But I respond with two points - France, where the Charlie Hebdo attacks took place, was founded on 3 principles - Liberty, Equality and Fraternity. France is a secular state, and that Liberty includes, however unfortunately, the freedom to insult others. I hate to wheel out this old line, but if you don't like living in a secular country with secular laws and people who have other religious beliefs (or no religious beliefs) and your own religious experience is so important and crucial to your existence, maybe you are living in the wrong country.
And secondly, how can you say you were insulted by someone drawing a cartoon? Unless YOU go and buy it, and YOU open your eyes and look at it, and YOU then come to a view that it's insulting, you seem to have gone out of your way to make yourself insulted. Were copies of Charlie Hebdo delivered to all the mosques in town? Did the rent big billboards and put the cartoon on display on street corners and roads and shops and on tv and at the movies and in your face? No. So when you say that my freedom ends where someone else's starts becomes a weaker argument when people have actually gone out of their way, and moved themselves into a position, so as to be insulted.
On another note, who is willing to wager whether or not there will be religiously inspired killings once the movie "Muhammad" is released, by IS style religious nutters who decide amongst themselves whether or not it's okay for a bunch of Iranians to make a movie about, and featuring an actor in the role of the prophet? Already there have been Sunnis saying the movie is blasphemous and sinful etc etc. Ironically the movie is supposed to correct the image about Islam being violent. Let's wait and see.