Christians are embarrassed about The Crusades and, to a certain extent, we should be.
At the same time, there is much misunderstanding of the context and the actual people who should be embarrassed.
Muslims were taking over the Holy Sites around Jerusalem. Christianity, under the Roman Empire, viewed itself as Israel Part Two. Therefore, when bad guys take over places in Israel; New Israel needs to go fight to restore it.
This is one reason why Christians need to take to heart the teaching that we are strangers and pilgrims. Once you start feeling attached to things on this earth, you will fight to protect them. You will kill.
People were recruited to fight The Crusades by a promise from the pope that their sins would be atoned for. Crusades were penitential pilgrimages with a little death and violence thrown in, often pillaging to pay for the trip.
When you read the Muslim take on Holy War and the Church’s teaching on Crusades, you realize quickly they were both promising the same thing–die for God while protecting His Stuff and you will be with Him in eternity. Neither realized God has no stuff here.
There was little difference between the Muslim and Christian thought patterns.
The fact that Christians walked around killing Jews and Muslims is a bad thing, but the issue Christians should be embarrassed about is not that.
The true embarrassment is that Christianity so quickly lost sight of eternity and fell for the bowl of pottage that temporal earth sold. It gave up it’s divinely created religion for a man-made sham religion. As C. S. Lewis said, we gave up a holiday at the beach to make mud pies in a puddle.
Catholic Theology set people up for the Crusades, teaching that sins could be worked off by an act of the flesh. Sins of the soul cannot be worked off by an act of the body.
This is a major reason I am a Dispensationalist. Israel and the Church are different. We’re not called to protect a spot on earth. Set your affections on things above. Where your treasure is, there will your heart be.
If you are fighting more for your country than for the Kingdom, don’t be surprised if you feel like killing those who oppose you. Hopefully you’ll pull yourself out of the trap before you actually do kill. (It still shocks me when Christians talk excitedly today about wanting to bomb terrorists into the stone age.)
We live for a better country. It’s what faith is all about.