Mark, that seems awfully narrow-minded on Fatima’s part. Some things are just easier to do with an axe than a gun.
Say you decided to smite someone at the neck (see Koran Sura 47:4: “Therefore, when ye meet the Unbelievers in fight, smite at their necks; at length, when ye have thoroughly subdued them, bind the captives firmly: therefore is the time for either generosity or ransom until the war lays down its burdens”). Or maybe, along with the neck, a fingertip or two is your style (see Sura 8:12: “Remember thy Lord inspired the angels with the message: ‘I am with you: give firmness to the Believers: I will instill terror into the hearts of the Unbelievers: Smite ye above their necks and smite all their fingertips off them”). Or perhaps you’re not neckly inclined at all, but you do have an urge to chop off a couple of hands or feet — from opposite sides, of course (see Sura 5:33: “The punishment of those who wage war against Allah and His Messenger, and strive with might and main for mischief throughout the land is: execution, or crucifixion, or the cutting off of hands and feet from opposite sides, or exile from the land”). Sometimes it’s not just about knowing what to do — you’ve got to have the right tool.
I’m certain though, that Fatima’s brother was probably motivated by poverty, Guantanamo Bay, Israel, Abu Ghraib, or even poor cartoon aesthetics. We can take comfort that his religious beliefs had absolutely nothing to do with it.