As far as I know, the military are one disciplined and coordinated group of people. The military environment is so coordinated with every activity well scheduled. The soldiers will only have time to gamble when they are free to gamble. It is not like they'll will spend every minute of their time everyday gambling. Moreover, the money they would win is not for themselves as gamblers. The chances of addiction are very low.
As far as you know... I guess you still have a lot to learn.
Those poor guys in military uniforms (been there, done that...) are nothing but ordinary young people trapped in some ideology. And they sacrifice themselves for what? I know the answer, so I will let you to think about it...
I don't know if this is true or not, but if gambling is possible while serving the country, it's like stealing money from those guys who serve. Think about it... You can't go out when you want, you don't have any girls near you, so you don't fuck, you don't feel love... so what will you do? Hey, you can gamble your hard-earned money in "our casino". Great idea for that government! Now they have a lot of desperate people who need money and they are ready to do anything you want from them... Craaazy!