Because by then religion didn't have much power over the governments of most of the world. Most Christian countries had converted to democracy, a secular check against the crusades that the churches may have wanted to launch.
While I am not religious, I do like the check-and-balance system between the secular and religious that most Western countries have.
Religions, churches are institutions of men. When the leaders of institutions place themselves into the role of being absolute (God's) authority on Earth, bad things are bound to happen.
While I am not religious, I do like the check-and-balance system between the secular and religious that most Western countries have.
If the faith of a people leads them to have bloody thirsty beliefs, secular "balance" is pretty useless.
About the only example I can recall of a regime ruled by a Christian overlord without any real checks and balances were the out-of-sight, out-of-mind colonies.
Suffice it to say that the Belgian Congo fails to impress as an indication that religion in and of itself prevents mass murder.