This is a pretty weird analogy... So A.I. is a centaur if you use it to great effect as a force multiplier to increase your output and everything works out. But you're a reverse centaur if you do the same thing but it ends up bad. The example given is a bestselling book list that normally takes a whole team to write up. Instead one person was tasked to do it but they fucked up because they didn't check if the books even existed and accidentally recommended fake books. The only difference to make them a "centaur" is if they or the A.I. didn't fuck up.
I do agree that there are some people who are essentially meat puppets of machines and do everything the machine tells them to. But it doesn't make sense in a productivity setting. It's more like both people are centaurs but one of them crashed into a wall and the other ran safely 3x faster