Well, loathing is sort of a loaded term. But aside from that:
Did Christians have a problem with Muslims before the Muslim conquest of Constantinople in 1453? How about before the Muslim Conquest of the Holy Land in 1077 (this is what started the Crusades)? Did Christians have a problem with Muslims before the Muslim conquest of Spain in about 700? How about before the Muslim wars against the Byzantine Empire in the 600's? Does the problem go back that far?
Boy, those Christians!
Yeah, Muslims have been trying to eliminate Christians from day 1. But all history seems to know is how evil those crusaders were. How dare Christians fight back.