Well, that's not so much an American thing, it's very general. I wouldn't even restrict it to nations only, it's a general "tribe" thing. It can even apply to video games and music, sports, and so on.

The worst part to me is that conflicts can very well be driven where people on all sorts of sides "reason" (it really has to be put in quotes I think) this way. With the result that attempts at fairness, any objections to double standards makes a person a perceived traitor to everybody deeply invested on the self-delusion of any of the sides.

From "Notes on Nationalism" by George Orwell: (as most if not all of his writings, it's available on the web and well worth a read)

> The nationalist not only does not disapprove of atrocities committed by his own side, but he has a remarkable capacity for not even hearing about them. For quite six years the English admirers of Hitler contrived not to learn of the existence of Dachau and Buchenwald. And those who are loudest in denouncing the German concentration camps are often quite unaware, or only very dimly aware, that there are also concentration camps in Russia. Huge events like the Ukraine famine of 1933, involving the deaths of millions of people, have actually escaped the attention of the majority of English Russophiles. Many English people have heard almost nothing about the extermination of German and Polish Jews during the present war. Their own antisemitism has caused this vast crime to bounce off their consciousness. In nationalist thought there are facts which are both true and untrue, known and unknown. A known fact may be so unbearable that it is habitually pushed aside and not allowed to enter into logical processes, or on the other hand it may enter into every calculation and yet never be admitted as a fact, even in one's own mind.

Something can be both a “terrible mistake” and also a violation of international law.

At a high level, it seems unlikely that American military leaders would intend to bomb a hospital, considering the horrible human toll and subsequent political and public relations disaster.

Perhaps the investigation will turn up a more complete story about why the hospital was targeted.

Yes, it is. A Congressionally declared war, even.

People tend to get hung up on the mistaken idea that Congress's power to declare war requires the use of magic words in the legislation in which it is exercised (e.g., that it has to use the words "declare" or "war"), but this is not the case. A Congressional "Authorization for the Use of Military Force" is a declaration of war (perhaps -- as was the case with both the 2001 open-ended 9/11 AUMF and 2003 Iraq AUMF -- a conditional declaration of war conditioned on a determination to be made by the executive, but a declaration of war nonetheless.)