The issue is that finitebanjo has conflated the two different meanings of Anarchy. Donpiano is talking about contemporary anarchism, a mode of governance without authority structures. One that argues that hierarchies and centralized power is the root of most of humanities ails. Governance is still performed, but it's on an individual level between peers where each member of the group is an active part in decision making.

Finitebanjo is talking about anarchy, the state of lawlessness that arises when the state fails to perform its governing duties. Most associated with riots and looting. The problem is when they call it "anarchism in it's truest form", they're conflating the state of lawlessness when the state abandons an area with a system of governance. It is not the same thing.

Anarchism is full of rules and laws, though. Arguably, one aspect of anarchism is replacing rulers with rules as far as possible, but that's possibly a contentious phrasing.