The number they are quoting is Dunbar's Number, a biological metric defining the cognitive limit on the number of stable, high-trust social relationships a human brain can maintain. The anthropological average is roughly one hundred and fifty. The argument often found in those spaces assumes that because informal, peer-to-peer trust degrades beyond this point, the only mechanism left to maintain cohesion is a vertical control plane, such as a central committee. This is an architectural failure of imagination that fundamentally conflates coordination with coercion.
Anarchist theory answers this by treating human organisation as a distributed systems engineering problem, demonstrating how architecture can scale without a master node. Authoritarian systems scale by building larger monoliths, which mathematically require middle managers to compress data from the bottom so the single executive node at the top can process it without crashing. Conversely, horizontal infrastructure scales by building an interconnected network of smaller communities, each kept to a size that operates on direct consensus and human trust, and then federating those nodes.
You can observe this architecture functioning in planetary-scale systems like Git, the Linux kernel, or the Fediverse. These ecosystems are built, maintained, and expanded by hundreds of thousands of people, not through vertical command, but through shared protocols. When local syndicates need to coordinate a massive project, they do not elect a president with sweeping authority. They send recallable, strictly mandated delegates to a regional council. The delegate possesses zero executive power over the node that sent them; they act simply as a routing mechanism, moving data between autonomous zones to establish consensus.
And hierarchies are fundamentally inefficient at scale because they introduce severe operational latency. If a worker on a factory floor identifies a critical failure, a hierarchical system requires that data to travel up the chain of command, await processing by an executive entirely divorced from the physical reality of the floor, and travel back down as an order. Horizontal networks optimise for local agency, granting the workers operating the machinery the autonomy to modify it directly, dropping the response time to zero.
The people telling you hierarchy is necessary are conflating structure with subjugation. Scale absolutely requires structure, logistics, and highly refined communication standards, but it does not require executive domination. The claim that humans can only build complex systems under the threat of authority is a cynical and scientifically illiterate view of our species.