Why would you say that?
If you'll grant me for the sake of argument that the war is justified, then the Iraqi people are every bit as guilty as we are. In both cases, we (and the Iraqis) have allowed our respective governments to do immoral things. The fact that Iraq is not a democracy might temper the blame that we assign, but the fact is that they've failed to rise up to overthrow their evil government. When evil things are being enabled by the contribution one makes to the society, it is (I believe) morally required that it be stopped. (And I note that I am guilty of failing to do so, underscoring the point of the OP)
I am similarly perplexed by people damning the US government, yet maintaining the nobility of our soldiers. If the war is wrong, then the soldiers are wrong for following the orders to fight it. "We did as we were told" is not a moral defense.
If we're talking about collateral damage _in Iraq_ though, it's reasonable to assume firstly that the American (civilian or otherwise) consciously chose to be there, which means they certainly accepted an elevated level of risks and secondly it is reasonably probable that they actively supported and are actively profiting from the war. Choosing a job with an oil company in Basra implies a much greater acceptance of the risks and ethical implications of being there than simply not choosing to overthrow the government. All you can tell about an Iraqi in Iraq is that they haven't managed to get out yet.
The hawk would no doubt approach with a different line; it is less probable that the American is actively or passively supporting hostile combatants attempting to prolong the war not to mention more likely the American happens to be their old buddy from school.
Either way both are making ostensibly reasonable value judgements.
I would say that our nation is us, and the same is true of the Iraqis. The bad things that my nation does (including the entity that it allows to govern) is my responsibility, especially because its acts are enabled because of my production (i.e., taxes, technology I develop, etc.).
The very same thing is true of Iraqis. They allowed their government to continue to run things the way they are.
You might argue that we live in a democracy, and thus change is easier for us. I would reply that (a) the form of government doesn't matter, in the final accounting a government cannot survive without the acquiescence of its people; and (b) fundamental changes in the USA might actually be more difficult, because its government is stable, entrenched, and incredibly strong.
It's actually an interesting reframing of the original problem: allowing a particular regime to remain in power and embark on a very wrong course of action might be the "least worst" option that is practically possible. In all but the worst case regime the rational utilitarians fearing the consequences of violent revolution actually find themselves in agreement with the pacifist absolutists.
It might be that a realistic examination reveals that regime change would be too "expensive", or risks failure either because the current regime wins, or because the replacement is no better ("the king is dead; long live the king").
However, given that analysis, it's still immoral to sit idly by and let events run their course. One would still have, at the very least, the obligation to (a) try to precipitate change in the long term; and (b) possibly contrive to minimize ones own contribution (by way of taxes and other support) to the current regime and its projects.
My impression is that the Iraqi people aren't doing a whole lot in either of those approaches (although I haven't studied it extensively, and what I do know is through the lens of the media). So while your claim may be correct in some cases, I don't see that it's applicable here.
In the article they said that conservatives favored killing the "black" man while liberals favored killing the "white" man. It isn't as clear as the background simply providing more data. The internal stereotype and moral values of the subject are also influencing it. It would be a terrible study if they had just lumped everyone into one big pool. It became interesting when they gathered other information about the subjects and then found correlations with their behavior.
Thus, it really isn't about what the common stereotypes are, but rather how two groups can perceive the same situation differently enough to make different decisions.
Thus my moral code is absolute, and I willing act immorally for a utilitarian outcome.
Similarly, when we talk about Tyrone vs. Chip, this is a question of a poor man vs. a rich man. But more to the point, "Chip Ellsworth III" evokes a sterotype of the rich Connecticut blueblood, a parasite aristocrat.
A much more interesting study would actually look at people in different clothes, with different skin tones. This just measures people's reaction to someone whose father was overly proud of his lineage and is likely a rich socialite.
Obviously this says something about my politics, but again it doesn't necessarily say anything vis-a-vis deontology vs. utilitarianism. Again, my impression of the name "Chip" is that he's a worthless individual who contributes nothing to society.
However, even if we assume that both are model citizens, it stands to reason that the death of the hypothetical lower-class black man is going to put his family through significant hardship, while Chip's family has enough money that mostly people will be getting a sudden unexpected influx of cash. So the question really becomes: kill one man, or kill one man and ruin his family's chance at a decent life.