To address the point that I think you're getting at, the difference between a military and civilian context is that is that the former is a potentially "no rule

To address the point that I think you're getting at, the difference between a military and civilian context is that is that the former is a potentially "no rules, everything at stake" situation. There is no international enforcement agency that can force all nations to abide by an agreed set of rules in any meaningful way. Thus, in a practical sense, there's no restriction on the type of weapons the enemy may develop and a nation must be on the cutting edge of military tech at all times "just in case". In the civilian context, enforcement agencies in most first-world countries are able to restrict weapons and violence reasonably well - most people won't see the need to arm themselves and will prefer to be law abiding. But in countries rife with violence where law enforcement is weak or corrupt, I imagine people would try to arm themselves with what they can regardless legal constraints.