Let us assume they are serious, and this “holacracy” is their real intent as opposed to the kind of window dressing that small companies use to mask their transition to big companies. It’s still hogwash.
Labor is conditional upon employment: one works because one is paid. People whose work is unsatisfactory are thus a negative value for their employers. So any company must have the capacity to end employment for those who do not work to the company’s goals.
Ah, but who defines such things? Who decides what are the company’s goals and what is “satisfactory”? Not everyone, surely: such would mean an infinity of mission statements (the horror!), and eventually, collapse.
So only certain people are given the authority to a) decide the goals, and b) reward or punish those who meet, exceed, or fail these goals.
Whoever these people are, whatever their title, however carefully the iron fist is swaddled in dainty gloves of pre-war velvet, they are the bosses. Whoever isn’t a boss is a worker. Et voila! Hierarchy.