While history is certainly important and often relevant, events which occured hundreds or thousands of years ago have no direct bearing on air carrier security today...

Islam is the only major religion that I am aware of which is currently condoning, preaching, supporting, and instigating overt hostile acts and terrorism.

Things are complicated since there is no single church hierearchy in islam, so your mileage may vary depending on which group of muslims you happen to be dealing with...many are totally above-board, peaceful, and law-abiding, but a many are not.

We don't want to paint an entire demographic with the same brush, but common sense dictates that you have to look where the smoke is to find the fire...