Eh, I think you are overstating our government's support of Israel, IN THIS INSTANCE. There have been other violent, widespread reactions to insults of the prophet emanating from other countries (that Dutch cartoonist certainly comes to mind).
When that Danish newspaper publishes those cartoons, per Wikipedia:
Four months later, Muslims protested across the Islamic world, some of which escalated into violence with instances of police firing on crowds of protestors resulting in a total of more than 100 reported deaths, including the bombing of the Danish embassy in Pakistan and setting fire to the Danish Embassies in Syria, Lebanon and Iran, storming European buildings, and burning the Danish, Dutch, Norwegian, French and German flags in Gaza City. Various groups, primarily in the Western world, responded by endorsing the Danish policies, including "Buy Danish" campaigns and other displays of support. Danish Prime Minister Anders Fogh Rasmussen described the controversy as Denmark's worst international crisis since World War II.
And Denmark is about as benign of a country in terms of foreign policy that you can find. No, this reaction and others has a lot more to do with the rampant religious extremism in that region than any other factor.