That's a really fair point and I agree to some extent.
But I also feel that if they were all atheist, there'd zero motivation to blow themselves up or drive trolleys through crowds while shouting Allahu Ackbar.
Even if they're frustrated from centuries of turmoil and need an outlet.
There's no way to prove what they might do, but it just seems logical they'd do more constructive things to ease their struggle.
they use whatever they need to in order to convince themselves that they're doing what's right and not what's wrong. keep in mind, people who live in incredibly poor living conditions tend to be much more religious; if the strongest, most inspiring part of your life is religion, then that's the place you're going to look to in order to justify and confirm the things that you're already doing and already believing. it's just the same with any other religion, the text is never used as literal guidance; people focus in on the details that make more sense to them. and additionally, the fact is, if you're born into a religious family, you're probably going to be religious too. most people who are religious were born into their faith rather than making a conscious choice to convert; these people hold their faith simply because they always have, and that's just a part of their world.
and terrorism/revolution is a political act. it's the last-resort effort of the people to try and correct the social contract when their government is entirely non-responsive to any other methods of representation. we've seen this happen everywhere, even today in america. the koran might give people ideas about specific attacks, but the idea that this is the only reason they're violent in the first place is absolutely bonkers. i find it incredibly difficult to believe that someone would read something in a god damned
book and then decide to commit Flash Mob and revolution. it simply doesn't happen on the kind of scale we're seeing. at the end of the day, the largest single factor in these attacks are political, because that is the only factor that offers tangible potential gains. esoteric promises in an abstract post-life world are difficult for humans to be largely motivated by; people do things because they seek immediate benefit, and finding an escape from political turmoil is one hell of a benefit for these people.