we both agree they are bad people simply put..
but my advice is..
that you need to understand your enemy.
you do not seem to understand them or even want to.
One does not need to understand that these khawarajites wether they are muslim or not,
A group of people will appear among you whose prayer, fasting and deeds will make you think little of your own prayer, fasting and deeds. They will recite the Qur'an, but it wil not get past their throats, and they will pass through the deen like an arrow passes through game. You look at the arrowhead, and you see nothing, and you look at the shaft, and you see nothing, and you look at the flights, and you see nothing. And you are in doubt about the notch."
This is what al-shabab do aswell as all the najdi's, they tell everyone your doing this and that haram, your a mushrik, you will go to hell.
Al-Shabab do not represent Islam, they have ruined the reputation of Islam, they have killed hundreds of muslims, including women and children, they have done acts o ghulum, wickedness, and wallahi if the prophet was here today he would not stand for such a thing, without a doubt.