Actually they can. It doesn't matter how many vote, it is who counts the votes that matters. In places such as Pa, Michigan or Wisconsin, where the election is likely to be close some concentrated ballot fraud in certain counties can tip the balance and the election. Biden is a senile boob and crook, but the rats know he has to win. For them it is existential. For the GOP not very much.
Joe Biden is trying to manage the issue.
BS Joe is trying to use it to show he is a voice of reason centrist.