For me, it’s a matter of practicality. Because sure, I’d love a perfect system in which everything operates entirely on voluntary cooperation, feel free to toss in a spherical cow with zero air resistance as well. But I don’t believe such a solution to be a practical option in reality, at least for the foreseeable future. Its basically a giant instance of the prisoners dillema, just at the scale of state militaries and nuclear weapons. And at that scale, I find it significantly more desirable to hedge our bets against bad actors than to rely on near universal acceptance of an ideal solution.