The crusades were in part instigated by Pope Urban whose help was sought by the Byzantines. The Muslims had been murdering Christians, destroying churches, etc. The crusades were, therefore, begun, as a war to STOP Islam. I think it was a good idea, but they just had a bunch of rag-tag people out there who really didn't know what they were doing; they weren't a real army. Everyone always acts like the Crusades were just some evil thing, but the actual reasoning behind them was in essence to stop Islam. Just my nutshell view.
Did they ever say it was killing in the name of God and that you would die and get 72 virgins?
Again not true. Declared by pope of Western Chruch. Eastern Church not once, not once have Crusade. We never and still do not accept Augustine Just War Doctrine of Catholic/Protestant world...oh and Orthodox is 300 million Christian and it is OUR lands that Islamics now try to steal: Russia, Serbia, Bosnia, Makedonia, Greece, Cyprus, Egypt, Sudan, Ethiopia, Armenia, Georgia, Bulgaria.