Fanatical religious extremeists are what's wrong with the world. Warmongers have used religion as an excuse almost ever since organized religion first started appearing hundreds/thousands of years ago. Think I'm nuts? In almost any war, both sides claim to be the just side and that they're destined to win because "God is on our side" or "We're fighting in the name of God" or something to that effect. Know what I say about that? BULLSHIT!!!
You don't fight wars because God told you to, you do it because you want to kill the enemy. In this particular case the attacks are (likely) to have been done by Muslim extremeists (who are fighting in the name of/because they were told by almighty ALLAH - which is simply they're name for God). They can go on all they want about how they're fighting for Allah and to defend Islam. We all know that it's all bullshit. They see what the Western world has in terms of money, influence/power, and resources, and they don't think it's right. They think the Muslim nations of the world should be the most wealthy and influencial.