Mandated reporting laws and how it applies to clergy-penitant privilege vary from state to state. In California, clegy-penitent privilege only applies to pastoral communications, so If the elders had learned of the abuse only from Campos himself they would not have had to report it, had but since they learned of the abuse from another source they should have reported it (assuming that law,was in effect at the time).
What makes me mad is that most religions retain clergy-penitant privilege to maintain confidentiality and protect the person involved, but the Watchtower doesn't care about that, they only care about protecting themselves. They keep records of any confessions that are made in the judicial committee, which belies the concept of such privilege. It's also not unknown for details of judicial committee hearings to be leaked by elders to their wives or others (except of course when it comes to pedophiles), which also weakens their claim of privilege.