Just like Christianity, most religions have been used by self-inflicted nutcases, over time.
The German Peasants' War (1524–1525)
The Second War of Kappel in the Old Swiss Confederacy (1531)
The Schmalkaldic War (1546–1547) in the Holy Roman Empire
The Eighty Years' War (1568–1648) in the Low Countries
The French Wars of Religion (1562–1598)
The Thirty Years' War (1618–1648), affecting the Holy Roman Empire including Habsburg Austria and Bohemia, France, Denmark and Sweden
The Wars of the Three Kingdoms (1639–1651), affecting England, Scotland and Ireland Scottish Reformation and Civil Wars
English Reformation and Civil War
Irish Confederate Wars and the Cromwellian conquest of Ireland