Comment by Gormo

You're motte-and-baileying here. Arguing that there are natural/desirable monopolies for government to possess in certain high-risk cases does not automatically translate into an argument that it's desirable for governments to have monopolies in every case imaginable. As a rule of thumb, it's best to avoid monopolies wherever possible, and rely on government solving complex coordination problems only as a last resort.

Pointing out that it's reasonable for governments to suppress private armies maurauding around and having wars with each other does not in any way sustain the argument that it's reasonable to allow governments to act as a forced intermediary in everyone's commercial transactions.