If you watch closely, Hillary's demeanor changes when he says that
To me, it is evidence that he already had the intelligence on her, and knew what she was doing.
I suspect he took off his gloves here for several reasons -
The Catholics aren't dumb and they are no strangers to the politics, optics, and problems surrounding pederasty. After this dinner they had to ask questions. Trump also, in that speech, indicated that Hillary hated Catholics. Hillary must have lost some support from the Catholics in New York after these admissions.
Hillary's biggest weakness has always been her arrogant recklessness. This is a simple tactic of baiting your enemy into making a mistake.