This statement is a fallacy. Cute, but false.

Firstly, Christianity as a movement has only been around for about two thousand years. Whether you go by the creationist 6 to 10 thousand year theory, or the evolutionist several million year theory, or whatever else, this leaves an awful lot of time floating around in which Christians haven't existed as a movement.

So there's anywhere from four thousand to several million years of time where wars were probably occuring (they generally do, with human life in the last, er, two hundred years as a nice example) without the religious movement known as "Christianity" being any kind of influence on that need for war.

People often point to the Crusades as one of the bigger "Christian" war efforts. However, much as there was noise about "freeing the Holy Land from the infidel", it's been rather widely recognized that much of what occured in the Crusades was a matter of expanding political horizons and merchantile concerns for various land owners, rather than an actual whole hearted religious concern.

Much of war, as a whole, is about "They have stuff/food/women/etc. we want, and they aren't going to respond kindly to "please", so we're just going to take it."

It can easily be argued that many hate crimes have been inspired by a Christian notion that the target is "out of the will of God, and thus must be defenestrated forthwith" by individuals who have twisted God to their own particular will.

This is true. Blaming actual population loss due to war, or outbreaks of war, on the Christian religious organization, is not only blind to history, but basically ignores the existence of Asia as a whole. *shrug*