Yes, you are completely right. The game divides us into two teams within a team.
But there are things even worse. This is launching key dialogs on behalf of the host. For example, in Act 3 at the final battle. This completely blocks cutscenes for the second player and their companion. Although it is the second player who should speak, since at this moment the quest line of his companion is involved.
I'd like to see some fixes for this mechanic for co-op play.
