Part of it is because Osama wants a war between Islam and the non-Muslim world and his allies in the Nuke Mecca Crowd are most happy to follow his orders and spout innanities that make ordinary Muslims think that the war on terror (such as killing radical terrorists) is a war on Islam (such as Nuking Mecca), despite what our President and all right-thinking people believe.
I really wish I could disagree with you...but I can't.