Several comments on the thread seem to not have read the article. Specifically: while they do not have "traditional people managers", they have people they call "Lead Links" and "Domain Leads" who take on management roles. It seems many are reading the title of the article and imagining a utopian experiment in total anarchy.
Giving managers titles that don't have the word "manager" in them doesn't mean that there aren't managers. Describing their responsibilities as being "mentor"-like rather than "managerial" doesn't mean they aren't, in fact, managing. The headline is rather explicitly stating that Medium is building a company with "no managers," and then the article goes on to describe some rather transparently bad attempts at euphemi…
The whole point in a role is to define who has decision-making authority over some given thing and/or what that role is responsible for. Lead links come about when a role becomes too big for a single person and turns into a circle which has its own members. The lead link is there to represent the circle to the parent circle and to determine who is filling what roles. Other than that, the circle is largely self governing (roles, responsibilities, etc are all decided in regular governance meetings as a circle, not by the lead link).
There are definitely decision makers at the company, but they're not managing people per se, they just have authority over some area of the company. The whole people side is entirely independent and generally lives outside of Holacracy.