How did the consequences of Pope Urban and Innocent III (1st and 4th crusades) go far beyond their intentions?

The Crusades intentions were to redirect excessive violence and an active military culture toward sacred ends. In March 1095 at the Council of Piacenza, ambadors sent by Byzantine Emperor Alexius I called for help with defending his empire against the Seljuk Turks. Later that year, at the Council of Clermont, Pope Urban II called upon all Christians to join a war against the Turks, promising those who died in the endeavor would receive immediate remission of their sins.[17]The first crusade unleashed a wave of impioned, personally felt pious Christian fury that was expressed in the macres of Jews that accompanied the movement of the Crusader mobs through Europe, as well as the violent treatment of "schismatic" Orthodox Christians of the east. During many of the attacks on Jews, local Bishops and Christians made attempts to protect Jews from the mobs that were ping through. Jews were often offered sanctuary in churches and other Christian buildings. In the 13th century, Crusades never expressed such a popular fever, and after Acre fell for the last time in 1291 and the Occitan Cathars were exterminated during the Albigensian Crusade, the crusading ideal became devalued by Papal justifications of political and territorial aggressions within Catholic Europe. The last crusading order of knights to hold territory was the Knights Hospitaller. After the final fall of Acre, they took control of the island of Rhodes, and in the sixteenth century, were driven to Malta, before being finally unseated by Napoleon Bonaparte in 1798. The Fourth Crusade was initiated in 1202 by Pope Innocent III, with the intention of invading the Holy Land through Egypt. Constantinople, after the Fourth Crusade, declined in strength and could no longer cope with the barbarians menacing it. Two centuries later the city fell an easy victim to the Turks. The responsibility for the disaster which gave the Turks a foothold in Europe rests on the heads of the Venetians and the French nobles. Their greed and lust for power turned the Fourth Crusade into a political adventure.