I seriously hate how the defense amounts to "many people have baselessly claimed this person is a pedophile, and while my client wasn't aware of any of these other baseless allegations until years into our ongoing litigation, it should still make it okay for us to also baselessly claim he's a pedophile too now!"
So, if enough of us all make the same baseless claim, then the legitimate basis for making that claim becomes "other people made the baseless claim, so I uncritically repeated it!" Just keep cycling a bunch of baseless allegations until the statute of limitations on the original baseless allegation has passed, and now we can all repeat it forever with impunity.
Why even have laws if you can break them by virtue of others also ostensibly breaking them?