Christian Violence in the Past Century
In the spring of 2013, Middle East historian Juan Cole decided to compare the body counts between violence committed by Christians and that committed by Muslims in the 20th century. He found that Muslim violence has claimed the lives of around 2 million people, mostly during the Iran-Iraq war and the war in Afghanistan, while violence by Christians claimed the lives of close to 100 million people. Here's what that looks like on a pie graph:

Some of this Christian-led violence is well-known: the World Wars, the Holocaust, the colonial wars in Southeast Asia and Africa. Critics of this analysis would be quick to say that this violence may have been by Christians, but it wasn't in the name of Christianity. But in virtually every conflict Cole ticks off, the combatants were overtly religious, and often invoked their religion as part of their military campaigns, just as many of the Islamist militants today are not fighting solely due to a religious grievance, but are organized around groups that share a common religious and cultural background.
But religion has played a more explicit role in some of the 20th-century conflicts involving Christians. For example, the 1990 sectarian warfare in the Balkans culminated in an explicit genocide against Muslim Bosnians by Serbian Orthodox Christians. As Balkans researcher Keith Doubt explained in a 2007 paper, the Serbian Orthodox Church was one of the prime movers in the campaign to scapegoat Bosnian Muslims and justify the eventual ethnic cleansing and genocide that took place. He notes that the role of the Church as protector of the Serbian nation gave the Church increasing social control, and with this power clergy fermented a xenophobic and bigoted attitude towards Muslims in former-Yugoslavia.
read more:
http://www.alternet.org/belief/despite-wingnut-freakout-obama-right-christian-violence-just-bad-muslim-violence