I was a Muslim for half my life, until I was almost twenty. The only thing I ever learned about Christianity I learned from my Imam and the scholars in the mosque. Then when I began to be trained in Madras we heard even more about Christians, that they are our enemies. I would guess that the key word that we would call the Americans was the Crusaders.
Of course, Ergun became a Christian when he was 16. And learned about Christianity probably while living from the age of 3 in Ohio. One wonders where these "Madras" were that he heard about Christians.