Muslims around the world have a thin skin. They cannot take a joke. Why is that??? It is because they are taught to take everything as a personal challenge. The "Prophet" Muhammad also had a thin skin and took any and all criticism and jest as a personal indictment. The slightest negative comment sent him into a violent rage. He had a poet (the ancient equivalent of a journalist) killed because she dared to publish criticism of his actions and his religion. It also did not help that she was Jewish, but that is another story. Muslims can give it, but they cannot receive it. They say (and the Koran says) all sorts of perverse, hate-filled, and untrue things about Christians and Jews, but Muslims cannot accept the same from Christians and Jews. My advice: Get over it, hypocrite. It's your turn. Now you know how the rest of the world feels.
Now for the cartoonist and the newspaper. If one has paid any attention to world events of the last five years, one would know that there are certain things you just don't do. Seemingly innocent cartoons can turn into riots and people getting killed. Apparently the cartoonist and the newspaper did not think very far ahead when they decided to publish this cartoon. I think it was a stupid decision to publish the cartoon. The newspaper should have excercised better judgement and discresion when deciding whether to publish the cartoon.
The majority of the blame should rest with the Muslims. They ultimately have the choice whether to react violently or to go on with their lives.