"Proof being the steep rise in suicide of current and ex military people who discover they cannot live with the regret for things they have done to fellow humans."
More important is the life losses suffered by ex-military that they have no chance of reinstating under a right-wing system of government:
Free health care.
Basic food and clothing.
To exit the military is to be thrust into the harsh competitive nature of a world that treats every individual as a resource to be exploited regardless of their skills, unless they have a lot of money, and then they can exploit other people. Most who join up don't come from anyplace that they had a chance to have money in the first place. They see no future for themselves and they used up their one shot to be valued by our militantly capitalist society.
Buying guns is an imaginary replacement for the latter. Guns are cheaper than buying a job, decency or mental health support.