Repudiable media outlets will generally avoid writing stories about unverifiable claims. But once you deny the claims, then repudiable media outlets can bypass the need for corroboration and write stories on your denials, while also detailing the claims you are denying, which just further spreads the content of the claims.
If the basic facts of the story are wrong, like the laptop or emails are not genuine, why don’t the Biden’s deny it?