Well, in the real world these days, kids are taking guns to school and shooting up the campus. When I was in school, worst thing that happen if you got busted with firecrackers, was a few days vacation from school, maybe an ass whooping at home. A pipe bomb gets you an introduction to an FBI agent, even just discussing it can get you an interview. Usually when a kid is planning to do something adults wouldn't approve, they don't advertise it.
I don't think this kid is a terrorist. or would actually build something like this himself. Might talk some other kid into it though. It's just not a good idea to make it simple and availiable to anybody who might be looking for the same info, different reasons... I've seen plenty of circuits and easily modified products on the web, that could be used for something like this. It's not like anybody is hiding some big secret, we just want to keep the damage to a minimal.
It's a different world these days, same dreams I guess. We were allowed to carry folding pocket knives in school, kids these days get kick out for a plastic knife in their lunchbox...