"However, the inconvenient truth is that after centuries of religious wars, Christendom long ago gave it up."

Christendom no longer has their own army but...

They still invest heavily in the war industry and support warring governments. I don't think they gave up their religious wars at all. Religious leaders are (Moslem, Jew and Christian) are quite willing to add fuel to the fire. Govts. and religions work hand in glove. Govts. do the dirty work and religion controls the people.