I'd say, remove those kids from their parental care, let Child Protective Services find a deprogramming program suitable for kids, and have the parents of those kids investigated by intelligence services.
I don't think many of their parents are islamists. Islamism is the new Beat-Music (or Grunge, Slipknot, First person shooters, MTV ...), and children - especially those from westernized households - pick the stuff up from Facebook and the like. A strict ban on cellphones, similar devices and internet usage (and Hiphop) for the underage, would solve this problem, and many more, like "cyber-bulliing", "happy-slapping", "cyber-slacking" and their general lack of movement. When I was a child, we didn't have cellphones, and the world was so much better back then.
Another thing, is this hysteric empathy that modern teachers display in religious education and in "special" dicussions after "tragic" events like the attacks on the World-Trade-Center or school shootings. For pupils, it is just fun, to troll the teacher by things like that. It is always fun - and strictly accurate - to remind them on the starving children in Africa, or traffic accidents. For teachers, and the media, a million deaths is a statistic and one death is a tragedy.
By the way: Look for the buzzword "je suis chien": 129 dead humans are a statistic and one dead dog is a tragedy.