The Crusades as a whole were a series of "defeats" due to the in-fighting among the Crusaders leaders, the straying of groups into Eastern Europe to persecute the Jewish people there, etc. However, the First Crusade (I believe) was the one that actually captured back some of the territory overrun by the scourge of Islam. They re-captured Antioch and Jerusalem and stemmed the growing tide of Islamic persecutions, rape, and pillaging. They also kept the Ishmaelites from conquering all of mainland Europe. Robert Spencer lays out what he believes the Crusades accomplished in his book on the subject and I tend to agree with him. Granted, the Khans and even another Muslim ruler helped stem this tide by attacking from the East. The unfortunate portion of your argument is that the small minority that are "moderate" Musllims are viewed by the majority as being heretics, blasphemers, etc. They are out there but they are fighting a very steep uphill battle. I agree that we should encourage this, but until a serious look at reforming Islam is taken by more of the clerics then these moderates will remain in the minority.
My original point about the Crusades was that they were DEFENSIVE in nature.