WWMG. Who is it that is feeling guilty? There are two factions on the muslim side in this war.
Faction 1, those who go to fight and are arrested or killed.
Faction 2, those who silently support faction 1, but don't want to die or be imprisoned. It is faction 2 who needs to be dealt with, since their tacit support drives the actions of their 'warriors'. In what form faction 2 would be dealt with I don't know, but I do know that as long as there is muted or no condemnation from the majority, the minority will continue with their savagery.