Okay - here's your mistake. The judgment on artificial nutrition and hydration was delivered in the course of a Papal Allocution to a conference. Such allocutions constitute an exercise of the Pope's teaching authority, and are routinely published in the Acta Apostolicae Sedis. Thus, what Pius XII says is fully applicable: "But if the Supreme Pontiffs in their official documents (Acta) purposely pass judgment on a matter up to that time under dispute, it is obvious that that matter, according to the mind and will of the Pontiffs, cannot be any longer considered a question open to discussion among theologians" (Humani generis §20).
On the other hand, in the case of the Iraq War, I'd note: I have never seen a quote by the Pope which condemned the war. Yes, the Vatican diplomatic policy was opposed to that, but that's not equivalent to official papal teaching published in the AAS which is clearly intended as binding.
I don't know the difference between allocution to a conference, acta . . ., Vatican diplomatic policy. No wonder it gets so confusing.
My only mistake was in asking the question. I honestly didn't know. How can that be a mistake. Maybe someone can simplify your explanation. Perhaps best to let it be for now. I've got quo primum running through my head now and don't want a flame war.