Let's look at this rationally. In the 1940's Harry Truman made the fateful decision that it was going to be us or them in the current, not both. The future we could be together but not at the time. At the time one had to prevail to break the impasse and stop the slow bleeding of both countries. So Harry nuked Japan and ended the war. He did this so his country men could live. they had to die so we could live. Who among you doubts for a second the nomad in some mountain fiddling with a plan to suprise nuke major US cities isn't looking at the calculus exactly like give em Hell Harry. They are postulating the simple fact that it comes down to us or them. For that reason be afraid, be very afraid. They'll do the deed the first chance they can. And their people will cheer them just like we cheered Truman. It's about survival. Odd are I wouldn't be writing this if Harry Truman didn't save my dad from getting shipped out to Guadacanal or wherever. Those plans changed forever when he sent the planes to Hiro and Nagasaki.
I doubt it. They're not thinking in those terms - Radical Muslims are at war with us - if we left them totally alone and withdrew our people from every Muslim country, they would come after us. They've been hitting us for years - trying to convince us a war is on - we've been ignoring them. Ignoring them until 9-11 made that impossible. So I don't agree with your assumptions. I suspect if we were to leave them alone, they would keep coming after us. Just like they have for decades.