My guess is that the reason for this “punishment” of being sent to the back despite already being the last is just a case of them following the rules despite it making no difference. Kinda like in hockey where someone is sitting in the penalty box, on team is up several goals, someone scores a goal and the penalized player is released despite there only being a few seconds left and no way for the losing team to make a come back…

Bothering by the book as it were.