The Crusades were not, mostly, fought in the defense of Europe.
What we normally think of as “The Crusades” were fought to recapture parts of the Middle East. They were a failed counterattack, not a defense.
There were, of course, “crusades” in Iberia, the Balkans and elsewhere that were in defense of Europe.
BTW, many “crusades” had nothing at all to do with Islam. The Popes launched them against Hussites, pagan Prussians, and even the Holy Roman Emperor and their domestic Italian enemies.
I seem to recall some pivotal battles in cities like Tours, France. What lands besides those of the Levant and parts of the old western Roman Empire did the Crusaders invade and keep—and that land only temporarily?
Take note of Obama’s use of “high horse”—as if sins that Christianity in general has repented of makes Christians have no leg to stand on for criticizing the “Muslim world” (as he calls it) for continuing those practices, which are of course justified in the Koran and Hadith.
No doubt battles like this one contribute to the idea that Muslims often attacked Europe (because they did)
http://en.wikipedia.org/wiki/Great_Siege_of_Malta
and these enemies were Persian, Ottoman Turks, Tunisians etc etc