Related to democracy, because the decisions are delegated to team vote, even though team is not experts in making those decisions.
The team voted, but they don't have real authority here. Could they vote to not make the decision? Could they vote to depose the manager and replace them with another teammate?
Your real problem is that the manager might be incompetent.
It is very common to delegate organizational work. But it only works if the manager exercises their competence to check and guide the work.