Well, I didn't get across to you what I was attempting.
What I meant by that was: Radical ideologies (like militant Islam) can appeal to vulnerable people anywhere...even natural-born citizens could fall victim to the siren song of eternal religious reward.
And that was my greater point, Islam and Christianity offer a terrible loophole: any wickedness you visit on your fellow men during your life is moot, as you are "forgiven" by your imaginary god. It is ridiculous, and it leads to all manner of ridiculous behaviour: from refusing medical treatment for your own children, to shooting non-believers in the streets of foreign capitals: it's all good, my god is great!
I don't think that leaving religion behind us would eliminate violence. I also don't think you really thought I was arguing that in the first place. I do think leaving religion behind us would remove another excuse for the use of violence when it is in no way necessary.
Paul, I don't think in many of the most egregious cases that it is the religion at work at all. I really think that there is a certain subset of humanity that just likes to hurt and kill. I think an organization like Daesh just gives them an excuse - a religious fig leaf - and a framework within which to sate their sadistic desires.