As I suspected, you misunderstand the position, or are deliberately distorting it. Read the chapter again, paying special attention to the section (which is 4 paragraphs long) which begins "But wars are very expensive,"
I've understood it fine.
If Joe has no defence agency, he can be killed. I take it you are agreed on that?
Deliberately distorting it then. Thanks for your honesty.
If he has no Defense agency, he is still capable of signing the same agreements to arbitrate with the other agencies as they are, he's just on his own for defense. Those who refuse protection would most likely be the "survivalist" types, and be armed to the teeth anyway.
Why should you have to pay for his ambulance ride? Why should anyone but him? It's his bill, let him pay it.
Are you gonna ask a critically injured person - do you have money? Or save him first?
Me? I don't run an ambulance service. But if I did, I'd find it hard to collect if my patients died while waiting for insurance to clear, so I would focus on keeping them alive first, and worry about payment later. Thus the use of the word "bill", as in "bill me later"