@ oldgrunt. As a military retiree (with 7 years law enforcement), I agree with some of your concerns . However, if, as you say, the military is reflective of society at large, how many of society go around shooting other brothers-at-arms, like police officers, for example? With gang-bangers there is no societal accountability, whereas service members have relatively high accountability at the squad and section level.
Yes, there are those who have returned from war with emotional and psychological scars, but that does not mean that because soldiers are allowed to conceal carry they are more likely to kill others. Since unit leaders are more likely to know whether a soldier has PTSD, or some other mental health issue that puts them at risk for harming self or others, command, in consultation with military mental health professionals, should have the authority to rescind a soldier's concealed carry on a case-by-case basis until cleared to carry again. Of note here, one of the screening questions for concealed carry permits concern those who have been institutionalized for mental health reasons within the past 5 years. Why can't the military have a similar policy for determining who can and cannot concealed carry?
The link below this forum states that an average of 22 military personnel per day commit suicide. One could argue that if all military personnel were cleared to concealed carry, the likelihood of suicide rates could go up. Possibly. However, while access to lethal means is always a consideration for determining risk of self harm, if a service member is determined to commit suicide, permit or no permit, they will succeed; unless effective intervention is applied.
Also, the same argument you use for not allowing concealed carry on military installations is what the 2nd amendment nay-sayers use. That if law-abiding Americans are allowed to concealed carry there will be murder and mayhem on the streets, which has been proven to be statistically false. And I believe that most Americans will agree that our military is overwhelmingly law-abiding.
To allow only officers and senior NCOs to conceal carry is condescending. If America and its military leaders trust 18 year-old E-1s to carry combat weapons on the battlefield, what makes them suddenly and mysteriously unreliable and unstable once they return stateside? Also, in a field environment, if a soldier doesn't have his or her assigned weapon on their person or in their immediate control, all hell will break loose. This is not a 2 + 2 = 4 scenario.
While I haven't fully developed my argument, obviously, there needs to be serious debate with a well-reasoned policy on the issue of allowing service members to conceal carry on military installations. And given the political climate in D.C., and the liberal anti-gun media in America, this isn't likely to happen in the near future.