Devon Stavrowsky on Quora. Stavrowsky is a former Army SF Medic, Cal Guard Officer, and Retired Cop (1968–2005). He writes:
Dark humor is a way in which people who have to deal with horrors and atrocities anesthetize themselves to them. Because you can’t be effective in what you are doing if you don’t inure yourself to them. In short order you’d just become essentially useless, unable to go back in and deal with the situations that generated the dark humor to begin-with the next time you encountered it.
You find it among soldiers and commonly among first responders as well. Civilians see horrors on TV or in the movies… read about them in books… but really don’t encounter them much. At least not in this country. And encountering the real thing is very different and profoundly affecting. All you have to do is look at the shock people go into when they occasionally do…. like around a bad car accident or after an earthquake or tornado.
When you have to deal with that sort of thing on a routine basis, you had better find a way to harden yourself to it, or you’re going to be in trouble… and not able to do your job.
Dark humor is just such a coping mechanism… and civilians don’t get the joke because they really haven’t been there, and you cannot explain it to people who haven’t been there.
It’s the same reason cops, after a while tend to hang out only with other cops, and combat veterans are very reluctant to speak of their experiences with anyone not a combat vet. If you haven’t been there… you are just not going to understand… and it cannot be truly explained to you in words that will make you understand. Words can get you sympathy (which is something you don’t want), and maybe respect, but they are never going to convey true understanding.