He's a terrible captain but ETH didn't have enough time to appoint a new one. He can't for example say it's Bruno then changes his mind few months later. So my guess is that he'll stick by Maguire for this season until a new leader emerges.
Yep, you must be inside the dressing room to know he is a terrible captain.
Hypothetically speaking, if Maguire is as terrible as you say as a captain, leaders and senior players would have spoken to Ten Hag about this.
Do you actually think Ten Hag has not had a conversation about this with the players? It was actually also well publicised he will vote.
Yet, after a weeks training, speaking to the players, the manager said he is captain.
If he hadn't have had a chance to appoint a new one, he could have easily said, I did not have enough time and he will look at this.