No offence, but this was islamic terror, read thenews. What explanation do you expect to find ? That there are muslims in America that try to teach every kid they can get their hands on to massacre their neighbors for not being muslims ?
Because if history is any guide, that's all you'll find.
Oh and it's the same story Russians (google "Beslan" and see how lucky the US has been so far), Britons, Spaniards, Chinese, Taiwanese, Philipinos, ... encounter. Which makes it very hard to believe those few extremely weak explanations like "it's the Iraq/Afghanistan war" that are given.
Sorry to state the obvious. Someone has to.
Let me just say : this is very likely to intensify from this point on. The attacks I mean. Why don't we just start the "but drone strikes justify random attacks on civilians" thread ? We all know it's coming. Don't expect me to post anything though.
I read it the same way.
Though, I don't think it's about literally learning from any individual, but to attempt to understand the underlying mechanisms.