Recognizing that Islam, like many other religions, can claim a large share of adherents who just want to get along - and recognizing that all religions harbor their share of zealot nutjobs (although Islam seems to harbor more than other religions, this is likely due to the sheer numbers of people involved) - a new category has been added, specifically for the nutjobs.
The case of the holy warrior may have belonged in the new nutjob category, but for a couple of issues: it appears that the boy was duped (and in fact nearly killed) by his "brothers in jihad", and that he now stands against al-quaeda.
It seems reasonable to use the Islam category in such cases, and to consign those involving al-quaeda and other barbaric nutballs to a category of their own.