Pakistan blocks facebook because some Westerners were having a Muhammad cartoon drawing contest.
In a single generation, people in many underdeveloped nations around the world have been catapulted from traditional local society into modern globalized societies. It has been an extremely difficult transition for many people, most visibly for people in many Muslim-majority nations. Americans take it for granted that in the United States, our modernization took place over more than a century. We had time for social movements to gradually challenge societal norms.
For example, In the 1920s-30s we experimented with prohibition, and then decided that drinking alcohol is OK. We came to accept political involvement of women early in the century as well with women's suffrage. Civil rights for minorities and women's liberation developed over the next few decades and culminated in the 60's. Acceptance of homosexuality has been a gradual process over the decades as well, and look how far we still have to go. Maintaining the separation of church and state, as the Founding Fathers intended, has been a constant battle - but it has been an important one, to keep religion out of politics.
Imagine if the USA of 1900 was thrust into 2010 in a matter of a couple of decades. America in 1900 afforded women and minorities few rights. Homosexual behavior was unthinkable, at least in public. People were far more religious and would have tolerated religious assaults far less than Americans do today. Alcohol would soon be made illegal. This is a world not hugely different than the one seen in many Muslim countries today.
Muslims around the world need to develop thicker skin. I believe the freedom of speech is the most important right that Americans have, and that means I have the right to draw a picture of Muhammad without being threatened for it. Liberal apologists of Islam in particular need to remember that - it is the fanatics who are threatening violence, and not the people who are drawing pictures of Muhammad, that are the problem here. That being said, the visceral reaction we see to something so innocuous, such as in the case of cartoons of Muhammad causing Muslims to flip out, is the result of basically a massive culture shock experienced in those Muslim nations.
Americans wouldn't have behaved any differently in 1900 if people in some other country were mocking Jesus Christ or desecrating Bibles. We would have thrown a temper tantrum, too.