For one thing, I doubt Austria would take kindly to Iraq doing inside their country what Israel does inside nearby countries and take extraterritorial military action. Especially when Austria was one of the nations that didn't want an invasion of Iraq and formally protested it.
Sure. How would that have done anything about this bombing plot? Or are you suggesting that Iraq should have killed this 18-year-old when he was still a minor? Because killing children intentionally is a war crime.
No but at that age they could have flipped him and give up others to take down. No needing to kill them or anything but just kind of put a dent in ISIS or get in one their plots and stop or warn people before they happen.
That's what I'm saying. Helmut the Cannibal is going to eat his face for trying to kill the lady with the voice of an angel and refusing to Shake It Off.