Alcoholism was and remains rampant, and in many cases even encouraged, as to keep the system 'lubricated'. Getting shitfaced on whatever you could find that'd get you there quickly is just an extension of that.
This is very much the same reason I'm not going back now. It saddens me that I may never step foot there again.
I've got a pretty vivid memory of seeing the 'recruiters' grabbing an amputee out of a wheelchair in broad daylight and shoving him in the back of the van along with the several other men they already had in there.
But when you are in it, putting on the uniform is the magic transition between the real you and vice corpral Rightbyte.
Loss of freedom is certainly the main factor.
Note, that my emphasis is on the system that make people behave strange.
It is somewhat ironic too, since being a soldier exposes you to so many practical and different problems that are so different each time that there is no room to be actually stupid.
And I am not talking about combat, but mundane stuff like, tying a rope between two trees to hang wet cloths on. In normal life people that would fail at stuff like this can get routine and hide that they can't do such tasks without messing up, but soldiers do so much different things that they don't get routine and if you are a bit off you are exposed.
If you are the kinda guy that can tie ropes between trees to dry cloths on, the military structure makes you behave like you would have been "stupid" in many situation that only is a problem because you lack power.
So Soviet or American sailors, that wanted booze but had no way to get it, solved it in the way they could. In civilian life they could just not have put them self in the situation where they couldn't buy booze.
Hazing is maybe a big problem since you are locked in with some jocks you can't escape since the front gate is guarded by MP.
Simple as that. The limitations make you stupid.
Like of someone tells you you tie your shoes in the wrong way you become a child mentally or something.