If you are ask to why the leadership (aka "Governing Body") of Jehovah's Witnesses does not freely advocate the report of child abuse to law enforcement, the reason is money. Where there is criminal litigation there is often civil litigation, especially if there is money to be had. Which is ironic as if the Watchtower policy had started with "Immediately notify local law enforcement and give them your full support" I am sure it would lessen the liability.
As far as rank and file Witnesses go - the organization is everything and does all the decision making. Literally - rank and file members live and die at the words of the organization. To them obedience to the organization equals salvation from Jehovah. To take action with out the expressed approval of the local body of elders is a deep and serious sin in their eyes.
This is why the comparison to child sacrifice to Muloch is no different then the scores of children sacrificed to the Watchtower.
This mindset goes beyond sex crimes involving child victims. It extends clear out to just about any criminal offense committed by any congregation member. Sure, the local body of elders will disfellowship the criminal offender, but in the end its all about maintaining the "reputation of the organization." It is never about protecting the public or pursuing justice. They excuse themselves by quoting Romans 12:19, but that has to deal with vengeance. Although those two things are similar, they are not one and the same.