There is a sense of puzzlement that help isn't sought. But in some MOS and some fields and some clearances seeking help is career suicide. Not all, but some. Not all soldiers are career and not all MOS and security clearances require no mental illness diag of course. So a soldier will only seek help if he's ready to pull the trigger on career suicide in which case doing the real thing is a microstep. You can tell people to seek help all you want to make you feel better about doing something, but if they know by example that their lifes work will be wiped out and they'll be unemployed in weeks if they actually follow thru and seek help, well, you do the math.
Second gaping hole is some of the support REMF (I was a REMF so I can use that acronym "proudly") have higher sec clearances than some front line. Naturally that means some front line both see some interesting stuff and if they get help for what they saw they might not lose their job. And the REMF now a days might get blown up in a convoy or IED or whatever as bad as a front line, yet if they seek help its bye bye MOS.
I have no personal experience with this, I was in during the early 90s but I kinda keep up with the times. There's an old saying about it being a rather permanent solution to a temporary problem. Young kids tend to have poor concept of time. A year in Korea is bad, but not worth offing yourself, unless you're a dumb kid, but then you don't want to speak ill of the dead, so ...
As with most big messes there is no simple solution and the more you know, the more complicated it is...