Eastern Christians dislike the 4th Crusaude which captured Constantinople for 70 years while looting everything in site. This weakened the eastern capital when it was recaptured by the byzantines, this weakening contributed to the Ottomon Turks succeeding in capturing Anatolia.
For the most part though, westerners have no clue of history and do not realize the Islamists stole Roman christian lands. To this very day the overwhelming majority of archaeological sites from Anatolia to Syria and Palestine are all Roman or pre-christian Greek. This includes the modern state of Israel where there are more greek and roman artificacts, and archaeological ruins than hebrew (or arabic or turkish). This is best seen by obtaining a Turkish travel brochure. Turkey is officially 99.2% Muslim yet the overwhelming majority of their tourist sites and museum artifacts are either, Greek, Armenian, or Byzantine in origin. In fact many of their abandoned villages are christian villages who had to flee during the population swaps.