Anyone have any explanation for this?
[1] https://www.publichealth.va.gov/epidemiology/studies/suicide...
From your question, I guess maybe you have the impression that "deployment" means "regular combat', or even "any combat". Maybe things will make more sense if you think about this as a comparison between "people who mostly stayed on base overseas/at sea" vs. "people who mostly stayed on base state-side". Most of the military is non-combat, and only a small percentage of even combat arms every see combat. (Also, the military is not exactly safe even when you don't deploy. Even with two active wars on, there have been years since 2001 when more troops died from non-combat accidents than from combat).
It's true that "war is 10% bullets and 90% logistics", but it's also true that the US runs its military as a sort of rural jobs program of last resort. So you're drawing from a highly vulnerable population to begin with, and then probably not deploying the bottom parts of that distribution. Guess which part of the distribution is also most likely to struggle finding work or getting through school post-deployment.
The mundane everyday reality of living in poverty in America is far more deadly than the battle fields.
Civilized war is silly