This, right here, would be the crux of The New Yorker's new story: the guy who says he heard about the Ramirez story second-hand referred The New Yorker to the guy who told him the story -- and that guy denied knowing about it. 
So we've got Ramirez's account, plus a similar account from a third party who heard about the incident -- but no confirmation from the other guy who told him the story, and presumably saw the incident. Once again, completely public incident, no first-hand witnesses.
This New Yorker piece also tries to claim that Kavanaugh being a bully in high school means that Ford's allegations are true. As someone who was viciously bullied in high school, that's absurd.
