Ooops! I just realized that I meant to say "overemphasizes" the political, on the ground situation. This is because I think he doesn't grant that there actually was a tremendous amount of idealism and faith involved in the Crusades, and if you read the writings of people - who bankrupted themselves, if they did not even die - going off to rescue other Christians, you will realize that they saw that there was a difference between Christianity and Islam and they knew that they were undertaking a great work.
I walked the Camino de Santiago a couple of years ago, and, with the reading I did about the Camino and at places I passed through, I came away with a real respect for the depth of commitment that Christians had to the ideals and beliefs of Christianity at that time. Yes, there was a lot of politics and even superstition and bizarre stuff, but on the whole, they had a concept of human life that we would recognize.
I met a young German doctor who was going to do the three great pilgrimages (Santiago, Rome and Jerusalem). He was afraid he would be killed on the way to Jerusalem, but he felt that it was important to do this. And probably our medieval ancestors felt the same way; after all, why shouldn't they have been able to go to Jerusalem, where Our Lord had walked?
Ooops again! My above post was meant for you...