These men and women in the armed forces are heroes... if you abandon the definition above and use a more useful definition. "A person who has qualities or performed acts which are useful to the community, who can serve as models for others, so that more people will act like them."
The second part of that definition is unhelpfully recursive... choosing to call people "heroes" or otherwise laud them is an important part of what turns them into models for others. To make that laudability part of the definition of heroism risks emptying the word of all content: heroism becomes anything we describe as heroic.
Leaving that aside... lots of things are useful to the community, so the first part of that definition covers a lot of ground. Using the model you suggest, it seems if I was to design a civilization from scratch that consumed food, presumably I would also label farmers "heroes," and if I was to design a civilization from scratch that produced organic wastes, presumably I would also label sewage engineers "heroes".
That doesn't seem to describe the world I live in. It would seem there's more to be explained.
The non-cynical explanation is that what makes soldiers unique is morale. We can encourage farmers and sewage engineers via steady monetary compensation, and we don't have to worry that hazardous manure will make them break and run, and if 5% of them were to suddenly quit then we'd be okay eating 95% as much food and paying some overtime to maintain the pipes. With soldiers, shit really does turn lethal, a 5% retreat can quickly cascade into a rout, and less mercenary compensation (using status and esteem instead of just money) seems to make such a rout ...
In the original When None Dare Urge Restraint post, Eliezer discusses the dangers of the "spiral of hate" that can develop when saying negative things about the Hated Enemy trumps saying accurate things. Specifically, he uses the example of how the 9/11 hijackers were widely criticized as "cowards," even though this vice in particular was surely not on their list. Over this past Memorial Day weekend, however, it seems like the exact mirror-image problem played out in nearly textbook form.
The trouble began when MSNBC host Chris Hayes noted* that he was uncomfortable with how people use the word "hero" to describe those who die in war -- in particular, because he thinks this sort of automatic valor attributed to the war dead makes it easier to justify future wars. And as you might expect, people went crazy in response, calling Hayes's comments "reprehensible and disgusting," something that "commie grad students would say," and that old chestnut, apparently offered without a hint of irony, "unAmerican." If you watch the video, you can tell that Hayes himself is really struggling to make the point, and by the end he definitely knew he was going to get in trouble, as he started backpedaling with a "but maybe I'm wrong about that." And of course, he apologized the very next day, basically stating that it was improper to have "opine[d] about the people who fight our wars, having never dodged a bullet or guarded a post or walked a mile in their boots."
This whole episode struck me as particularly frightening, mostly because Hayes wasn't even offering a criticism. Soldiers in the American military are, of course, an untouchable target, and I would hardly expect any attack on soldiers to be well received, no matter how grounded. But what genuinely surprised me in this case was that Hayes was merely saying "let's not automatically apply the single most valorizing word we have, because that might cause future wars, and thus future war deaths." But apparently anything less than maximum praise was not only incorrect, but offensive.
Of course, there's no shortage of rationality failures in political discourse, and I'm obviously not intending this post as a political statement about any particular war, policy, candidate, etc. But I think this example is worth mentioning, for two main reasons. First, it's just such a textbook example of the exact sort of problem discussed in Eliezer's original post, in a purer form than I can recall seeing since 9/11 itself. I don't imagine many LW members need convincing in this regard, but I do think there's value in being mindful of this sort of problem on the national stage, even if we're not going to start arguing politics ourselves.
But second, I think this episode says something not just about nationalism, but about how people approach death more generally. Of course, we're all familiar with afterlifism/"they're-in-a-better-place"-style rationalizations of death, but labeling a death as "heroic" can be a similar sort of rationalization. If a death is "heroic," then there's at least some kind of silver lining, some sense of justification, if only partial justification. The movie might not be happy, but it can still go on, and there's at least a chance to play inspiring music. So there's an obvious temptation to label death as "heroic" as much as possible -- I'm reminded of how people tried to call the 9/11 victims "heroes," apparently because they had the great courage to work in buildings that were targeted in a terrorist attack.
If a death is just a tragedy, however, you're left with a more painful situation. You have to acknowledge that yes, really, the world isn't fair, and yes, really, thousands of people -- even the Good Guy's soldiers! -- might be dying for no good reason at all. And even for those who don't really believe in an afterlife, facing death on such a large scale without the "heroic" modifier might just be too painful. The obvious problem, of course -- and Hayes's original point -- is that this sort of death-anesthetic makes it all too easy to numb yourself to more death. If you really care about the problem, you have to face the sheer tragedy of it. Sometimes, all you can say is "we shall have to work faster." And I think that lesson's as appropriate on Memorial Day as any other.
*I apologize that this clip is inserted into a rather low-brow attack video. At the time of posting it was the only link on Youtube I could find, and I wanted something accessible.