They are relying on the Right being more moral on this than they are and backing down. But, it looks like the there are enough people on the Right who are willing to act like the Left, so this will keep going, regardless. (And, maybe the allegations are true.)
Agree that promulgating fake claims for political purpose is bad. The Left did it with Kavanaugh, and they did it with Trump (although I recognize that Trump had affairs and sexual interactions with groupies). They don't want the Right to do it.
Note that I don't know if her claims are not valid. I haven't bothered to inform myself on them, since they won't change how I vote. I just love the theater of the Left being hoisted on their petard. And, after all, I've known Biden was a creeper for a long time now...there is quite a lot of video of his behavior with women. No "penetration" video, but lost of video related to her groping allegations. Lots of accusations against Trump as well, of course.
But, per the Left, we really need a national discussion on this. That is what they want. That is what they should get.