Two points:
1) USA Bro acts childish because HE'S STILL A CHILD!
He may grow out of it. Most kids are morons, and, somehow, eventually turn into adults. They are easily impressionable, and, well, whatever environment Bro is in must be a DOOZY.
As a teen, he is still developing (Despite his own goofy estimates of development patterns), and, one day, may HAVE critical thinking skills. We all mature at different rates, and that's not just in responsibility, its in ABILITY to think, and, for different processes, it takes different people different lengths of time. If Bro was 20, I'd say this batch went bad, and it was all over for him. But he's just 16 or so, and, still in the oven.
It would be NICE to see him grow up here, and evolve into a man from a boy, learn to think on his own, and so forth.
I'd vote to give him time, but, still smack his ass when he's out of line, so he can LEARN what is hateful and/or stupid, and, what is reasonable and/or kind.
ESPECIALLY in that religion thread, where the POINT is to discuss how we feel, etc. He's ALLOWED to be wrong (Spectacularly), and, when its pointed out that he's wrong, and why...one day, he might be ABLE TO actually consider why...and how it fits or doesn't into his puerile world view, and, if the world and Bro are lucky, maybe even adjust his world view to reflect reality instead of the hateful propaganda he's been inoculated with.
2) I think ISIS is, as an organization, not stupid. They are playing their cards fairly intelligently, and, except for being blinded by their warped version of religion, doing pretty well.
The being blinded part, of course, will be their downfall, as they will tend to overestimate their own power to recruit, and underestimate the rest of the world's ability to rally against them if they cross certain boundaries.
Terror only works if you terrify your opponents into inaction/attempts at appeasement, etc.
Terror backfires when your atrocities enrage and incite your opponents to act.
Its harder to terrorize a government than a person. The govs send people to fight, not themselves, and are far more likely to be unafraid of action.