WE SHOULDN'T BE SURPRISED BY THE AMOUNT OF WAR AND GENOCIDE SUPPORTED BY CHRISTIANS BECAUSE THE BIBLE IS FULL OF IT.
I will punish the Amalekites for what they did to Israel when they waylaid them as they came up from Egypt. Now go, attack the Amalekites and totally destroy all that belongs to them. Do not spare them; put to death men and women, children and infants, cattle and sheep, camels and donkeys.
-1 Samuel 15:2-3
From the Crusades to Afghanistan, religion plays a part in almost every major war. Like slavery, God not only approves of war in his name but also actively encourages it. Throughout the Bible, God orders the obliteration of groups of people that He views as enemies. Christians historically have used the Bible to justify wars they deem righteous. For example, the wrath of the Catholics during the Inquisition should come as no surprise when you actually read how the Bible promotes this type of behavior.
If you hear it said about one of the towns the LORD your God is giving you to live in that troublemakers have arisen among you and have led the people of their town astray, saying, "Let us go and worship other gods"… then you must certainly put to the sword all who live in that town. You must destroy it completely, both its people and its livestock. You are to gather all the plunder of the town into the middle of the public square and completely burn the town and all its plunder as a whole burnt offering to the LORD your God. That town is to remain a ruin forever, never to be rebuilt… -Deuteronomy 13:12-16