The interesting part about that to me is that they don't regard the fleecing-children part to be "giant harm." I.e., the court has records that are even more damaging to Facebook.
Or they think in that case, the public benefit outweighs the damage to Facebook.
This is much more likely IMO. The public benefit of different pieces of information can vary greatly, with most probably approaching zero. Even if the child-fleecing stuff was the most harmful of anything to FB, it's still reasonable that other things are not beneficial enough to release even if they likely are not as damaging.
That's really troubling. But by now several people have access to this information anyway, so it's just a question of time before we learn what it was.