Also this sounds like the “no true Scotsman” thing. Some of the people in the zone were self described anarchists, they were setting up co ops and volunteer medical services, and if it had succeeded (meaning, not been overrun by violent crime) I’m sure people would have pointed to it as a model of anarchist principles in action.
It also doesn't sound very anarchist to prevent others from using your accumulated property with hired guns. That's the basis of capitalism!
Ancaps and anarchists have very little to do with each other, actually.
edit: to make it clear, I don’t want to “safeguard” the word anarchism, I don’t really care, I’m not part of that movement. But the anarchists that wrote the original article are part of a movement that take anarchism to mean something, while ancaps make it mean something entirely different.