You're overthinking this. They were required to report. Several states in Australia require mandatory reporting and the WT authorities (elders, etc.) still failed to report 100% of the time.
That being said, it was brought out in the inquiry that in alll of Australia there is a legal concept know as misprision. According to this principal all citizens are required to report any and all criminal to the authorities. Again, the WT authorities (elders, etc.) still failed to report 100% of the time.
Over 65 years, 1,006 known abusers, and the WT leadership dropped the ball every time. Every time.
The scope of this failure is simply spectacular.