It’s obviously an overly legalistic and technical argument that doesn’t speak to the merits. But it’s an appeals case, you have to argue legal errors not factual ones. I’m not a lawyer and have no idea how likely it is to succeed, but I think “throw everything at the wall and see what sticks” is best legal practice, so I don’t see how this filing hangs him out to dry. It’s bad optics but I don’t think is gonna matter to anyone.
he was also all geared up to run in 2016, but then his son died. If I recall, Hilary Clinton actually waited for Biden to decide he couldn’t run before she entered the race.