I love it when someone brings up the "old enough to fight and die, old enough to smoke" canard. The military knows kids better than most. The fully understand children are not capable, as a rule, of making good decisions which is why they are provided full time sitters and live in dorms (barracks) until they prove, individually, they deserve some say in the decision making. Civilian kids are simply granted certain privedges at certain ages. In the military, one earns the ability to make decisions The military understands the basic immaturity of late teens and early twenties types. Granted, ages of majority are certainly arbitrary but, limits are for the lowest common denominator. More mature members earn freedoms faster than their less bright/tractable peers. That is the intention anyway.
The military easily and severely restricts smoking with regard to age, times, locations, etc. It has been that way for years. Somebody with more stripes and experience determined when one could smoke and where. It was totally prohibited the first three weeks of basic training in my time. And then the DI taught us how to smoke and not litter. I remember "field striping" fondly. Policing smoking areas wasn't a lot of fun either. Society tolerates slovenly behavior. The military? Not so much.
They, the military leadership want to reduce physical damage to property as such is expensive. The same as civilian building supers, landlords and others. Limiting the inconvenience to non-smokers is something the military finds useful and easy to implement. Friday Night Smokers in the NCO Club are mostly relegated to history and the memories of "the good old days." Just as the military was forced to lead the fight to integrate society, work forces, neighborhoods and schools it may be the logical leader to relegating smoking with regard to age appropriateness and such. By it's nature the military commitment to "control" lends itself to social restructuring. It is what they do best after all. Well, along with the noble goals of "killing others and breaking stuff."
Civilian and military smoking is generally perceived as "anti-social" behavior. Deal with it guys! We've reverted back to pre-WWI days with regard to tolerance in smoking. Well, can't smoke in the gaming halls and bars these days. That's a bit more severe than the so-called "good ol' days."