Because: 'You are not Muslim or you are not Muslim enough... for them'.

http://www.iht.com/articles/2006/04/28/opinion/edmona.php Once again, for Muslims, it's 'us versus us' - International Herald Tribune, France - If anyone is on a crusade against Muslims it is Al Qaeda itself, whose sympathizers most likely carried out the attack in Dahab, the third in Sinai in 18 months ...

Congratulation mainstream media, finally you see that, Will you also see how "palestinian" Islamists are their people's (especially their own children's) greatest enemy?

Then again it all (Al Qaida, Hamas, Hezbullah, Islamic Jihad, Hitleristic Iranian Islamic Regime, Jemma Islamyia, Chechnya, Abu Sayyaf, Sudan genocide, you name it...) boils down to one thing:
'You are not Muslim or you are not Muslim enough... for them'.