Islam emerged from what is modern day Saudi Arabia in the 7th century, and never looked back. Muslim armies swept across North Africa and invaded Catholic Spain, destroying or converting the Christian communities along the way. They turned churches into mosques, and made Islam the official religion. Muslim armies also took over the Holy Land, destroyed the last non-Islamic Persian empire, and moved into Asia Minor (modern day Turkey). By the 16th century, Islam had destroyed the Christian Byzantine Empire, had taken over Constantinople, and had turned the Hagia Sophia -- the most beautiful church in Christendom -- into a mosque. A century later, Muslim armies were outside the gates of Vienna.
While the years have passed and the names of the armies and countries have changed, Islam's war against the rest of us continues at full speed. There isn't a day that goes by without a new terrorist attack carried out by a Muslim militant. Women are stoned in Afghanistan because they had the nerve to be raped... Children are beaten to death and strung up in Pakistan, because they were suspected of theft... Non-Muslims living in Muslim countries are in constant fear of kidnapping and murder... It's even happening here. In Buffalo, New York, a Muslim-American television executive who attempted to use his station to improve U.S public opinion about Muslims later beheaded his wife after she filed for divorce. Of the roughly 25 wars currently ongoing, 21 involve Muslim countries. Put differently, Islam is connected to 80% of the planet's armed conflicts, while making up only 20% of its population. There's a reason for that.
In Islam the world exists in two Houses. The House of Peace, where Islam is the recognized religion, and the House of War, where Islam is fighting to become the recognized religion, and because Islam teaches that Allah may change his mind at any time, for Muslims, there is no stable and universal moral code. When you eliminate reason as a guide in human thinking, force is the only thing that determines truth. For that reason, in the House of War, anything goes.
In regard to the Park51 mosque, both critics and supporters are getting the context wrong. They're framing the debate as if it were a New York or American affair -- a local dispute over land use. This is dangerously naive. The context isn't New York in the year 2010, but the whole world since the seventh century. If you ignore that, you miss the entire point, and are reduced to explaining the protests as examples of bigotry or religious intolerance.