Art, maybe...but who did Belgium invade, for example. I was getting at something else though. 

In the cases I mentioned, these were not very religious men. They are petty criminals, drug users, etc. What are they attacking for? What is/was the trigger for their action? The London, Paris incidents seem ad-hoc. No notes, videos, explanations, little planning, few weapons etc.  Were they mentally ill? Were they on narcotics? Is there a toxicology report coming? Were they coerced or blackmailed by someone?

Much is being made of the London attacker's WhatsApp message 2 minutes before the attack. While the actual message may be encrypted, WhatsApp should be able to state who the message was to/from, as well as the accounts of ALL people he corresponded with in the last few days. Patterns could be detected. e.g. A sudden rise in messages to people in the last 2 days could indicate accomplices etc.  Seems obvious but why is this not done? "He was radicalized. Case closed." Strange, no?