No, Islamic terrorists are not a theory, they are real, organized, financed, enemies of everyone non-Muslim, in the world. It wouldn't matter what one wishes to call them. The simple fact that they are hostile enough to kill thousands of people (millions if they can gain possession of nukes), is enough to fight to stop them from attacking us again, as they have already, on numerous occasions.
As for bombing Dublin, I see no parallel between that and the US and coalition troops in Afghanistan, fighting to deny al Qaeda bomb training quarters, and neutralize Pakistan's nukes.
You don't need to grow up. You just need to get a realistic grip on what's going on in the world. And the concept of a STATE which you seem to be dwelling on, has absolutely NOTHING to do with this. In fact, by all real definitions of a state (a nation), Afghanistan has really never ever been one. What has always appeared to be it's outer borders are actually the outer borders of the nations surrounding it. even if it were to be defined as a State, the coalition isn't fighting against Afghanistan, it is fighting against al Qaeda and the radical Islamists who are trying to attack all the rest of us, and would annihilate us all if they could get their hands of the 100+ nukes in Pakistan.