The world is not black and white. There are not just trump supporters and Biden supporters. I know it's hard to grasp but there are tons of people in the the toss up category.
You're right that this probably won't penetrate the deeply perverted world of trump cultists, but the wh doesn't expect to win the brainwashed over. They are going for those people who could go one way or another.
So, the race is basically already decided but there is a conspiracy among the media and polling companies to make it look like the race is actually close and that there are undecides. Of course, the only way to prove this wrong would be with polls, but we've conveniently already just rejected that evidence. Very convenient.