It wasn't a private audience.  O'Reilly got a handshake from Pope Francis and a picture in the VIP line at the Wednesday audience.  There is a huge difference to that.  

O'Reilly unfortunately does have connections to the NYC dioceses which is why he was able to score the good tickets.  (Money talks, especially to Timmy Dolan.)  I mentioned in the past that O'Reilly used the Church to bully his ex-wife by having them send a threatening letter because she remarried without an annulment and was receiving Communion.  That is the only way that the Church could have found out about that and the only way they would have cared.