
They seriously fuck with your brain and your body. If you want functional soldiers, substance dependency is probably not a good choice. People on gear also have a tendency to drop dead of heart problems in their 40s and are prone to roid raging, which could create issues with chain of command stuff
I actually believe your first point is valid. The second point people drop dead to a bullet to the head and your a soldier, what the life expectancy of active duty soldiers/vets? To your third point, the military has dealt with people with anger issues, this is no different than that.