That's a different situation. In self defense you're most likely facing a single or maybe low number of opponents, who most likely have little to no training, who most likely have no armor. In this case hollow points are good because they expand on impact and dump the majority of their energy into the target.
In a situation of collective defense you're more likely to face a societal breakdown scenario, so armored opponents become more likely. Armories will eventually be raided, and even an average police station has hard armor/soft armor on hand. In this situation ball ammunition is the go to because it's plentiful, reliable, and generally good enough. It's not armor piercing, but at this level of combat training and resources are going to be the deciding factor essentially 99% of the time.
But what about collective defence?
That's a different situation. In self defense you're most likely facing a single or maybe low number of opponents, who most likely have little to no training, who most likely have no armor. In this case hollow points are good because they expand on impact and dump the majority of their energy into the target.
In a situation of collective defense you're more likely to face a societal breakdown scenario, so armored opponents become more likely. Armories will eventually be raided, and even an average police station has hard armor/soft armor on hand. In this situation ball ammunition is the go to because it's plentiful, reliable, and generally good enough. It's not armor piercing, but at this level of combat training and resources are going to be the deciding factor essentially 99% of the time.