There's safety in numbers. Swalwell was a powerful politician with the ability and finances to file defamation lawsuits against any single person coming forward.
Now that there are a number of them and the media finally on their side, they don't have to worry about the lawsuits.
As an example, look at that bitch that claimed Trump assaulter her. She was proven to be a liar by the jury, but that didn't protect Trump from the defamation lawsuit he lost but is now being appealed.
There may be safety in numbers, but as time goes by evidence is lost and any proof is compromised. (And as someone else noted, people are still damaged without proof in these cases, as Trump has been in the Carroll case. Nowadays, someone can wait 20 years and then destroy a man with mere accusations and no proof at all!)
Swallwell is a crude, disgusting person, but politics don’t change my principles in this. We’re been living for decades in an atmosphere where a completely innocent man can have his life destroyed because a woman just points a finger, and a corrupt political machine finds her lies useful.