I found the argument weak as well when I first encountered it. But as I got older I realized something important into the game theory. If all but one power had no weapons then this means that if that singular power decides to be aggressive, then they will have the ability to take from the rest. I then realized that weapons are fairly ubiquitous in that neither can you have defensive systems that can't be used offensively nor can you have a lot of engineering without also having weapons related technologies. This to me doesn't mean we need a military industrial complex, but it does mean, to me, that we need some minimal military. It does also mean that as citizens we should protest needless violence by our countries. (And if the US is going to act as world police regardless, we need to ensure that situations we engage in are moral. E.g. you could support Ukraine's fight for freedom but not the war in Iraq). The real world is extremely complex.
I'd love to live in a world without weapons, but I don't see how such a thing is even possible, from multiple angles. If that's not possible, then it is about how to minimize fighting and lives lost. After all, that is why we'd want no weapons. That solution space is rather complex and likely non-convex.