As opposed to being founded on stealing other people's stuff.
"You mean I don't have to wander around the land responding to threats, you'll do that for me? If someone else comes around and threatens me, I can just point them to you? I can sit here and just figure out how to increase my YoY crop? Buddy, you don't have to coerce me, just swing by every month and we'll wine and dine the fuck out of you! I sure hope you brought all your horses because you're gonna need em!"
Warlords were like helicopter bosses. Annoying, but they don't stick around long enough to really mess with anything. It's those with misplaced senses of justice that really got a bee under their bonnet over it. Same as today.
it's not always pretty (and needs regulation to prevent monopoly formation, which the US currently lacks) but the alternative systems with involuntary transactions are demonstrably worse.
When one party is hungry, and the other is not, voluntary participation does not imply freedom of choice.