To be sure, US criminal investigators have not officially identified the motives of the Kuwaiti-born Abdulazeez, who does not seem to have belonged to a terror network. But there is plenty of precedent for an alienated and disenchanted young man, brought up in the West (Abdulazeez attended high school and college in Chattanooga), to seek a cause worth fighting for – and to find it in the perceived humiliation of Islam by America and the West.