Cultures change. What is overlooked about the Crusaders, and the knights and nobility of the 10th century and thereabouts, is that they were very bloody-minded. They had been raised since infancy to devote themselves to fighting. They were very sinful. They particularly were into coveting wives. And they were very religious.I don't know why, but that quote from this interview with Rodney Stark amused me a great deal. I hope you find a few minutes to read it all the way through.
The fact that these things can be combined strikes the modern mind as bizarre. But you have to deal with it if you're going to understand these people. They would commit a horrid crime, and their confessor would say, "I don't know if you can ever get over that one. I don't know if atonement is in the books for you. But you better walk barefoot to the Holy Land and hope that that works."
And they'd go. And then come back and sin some more.
It takes some stretching to understand what motivated these people.
h/t First Thoughts