Who are you kidding using the Crusades. The whole reason the Crusades happened was because Muslim armies conquered it from Christians in 1076. Muslims were threatening to capture Constantinople. Christians were being massacred and persecuted by the Muslim over lords who had taken over Israel and Jerusalem.
When the Muslims moved towards Constantinople in 1097 over 10,000 Christians mounted in Constantinople to take back the holy land from the oppressive Muslim's. The first Crusade managed to recapture Israel in 1099. The Crusaders butchered everyone within the walls, pretty much. However during that time period the Muslim armies did similiar acts of genocide against the Christians.
During the four crusades horrible acts of genocide and war crimes were commited by the Muslims and the Christian's alike. Muslims killed and persecuted thousands of Christians if not millions, this was the reason the Crusades happened to begin with. If Muslim armies hadn't taken over Jerusalem in the first place none of the crusades would have occured.
It was Islamist oppression that sparked the Crusades. Though I agree the Crusaders did horrible things the Muslims weren't much better.
Also during the second Crusade Muslims were allowed to visit Jerusalem and worship in their mosques. Saladin also took all those who couldn't afford a ransom into slavery when he took Jerusalem.
In the end Christianity matured. Islam did not. The Bible (New Testiment) preaches peace and love with all non-believers where as the Qur'an tells Muslims to kill infidel. Their is a drastic difference between the two faiths. Today Muslim countries force Christian's to convert or be killed and kill any Muslim's who convert to Christianity.
Islam is stuck in the dark ages (In the Middle East), the rest of the world has matured. Islam as a religion is extremely oppressive. I love my Muslim brothers but what the Muslim Governments are doing in the middle east and north africa is unnacceptable.