Simple answer : Because the governing body & WT Society leaders do not recognize the laws of the land as having authority over them. They only allow themselves to follow the Bible's 2 witness rule, even though this endangers children. And within that simple answer is that the financial empire the WT Society wishes to protect to keep them financially solvent. Money first, children's welfare way down low on the list of priorities.
In regards to the WT Society's leaders life being made easier by cooperating with authorities in reporting child abuse ? Uh, not really. It would expose them more fully in the wide open light as a criminal organization hiding all of these sexual predators of children and bring MORE attention in the media to WT Society cover ups - just like the media exposed Warren Jeffs and the Mormon's and also how the media exposed the Catholic church even more. Catholic church is still being exposed with all the pedophile priests molesting minor children.
I think WT leaders are intentionally trying to stay on the down low- and they think this will make their life easier . If all the child abuse was fully exposed- we'd see an absolute shit storm of media coverage . I wish that would happen, but WT keeps trying to sidestep and hide in the shadows. We need more Leah Remini's out there exposing these crimes of the WT Society. Peace out, Mr. Flipper