The military doesn't issue anyone ammunition to defend themselves with. Forget that idea, right out of the gate.
The logic is simple, if a bit brutal. Protecting the individual soldier's life is not priority #1. Completing the mission, is.
We use FMJ ("ball") simply because it functions the best under all possible conditions. The fact that it also complies with the Hague accords (which we never signed) is simply a plus. The military accepts the fact that the FMJ bullet is the least efficient in stopping power, compared to SP and HP designs, but in their view, the reliable feeding of FMJ over other designs outweighs its inefficiency.
Put another way, a ball round that feeds and fired is worth more than an SP or HP that jams and doesn't fire.
As a civilian, I take the opposite view, protecting my personal posterior (and my loved ones) is job #1. we just have different priorities is all.