It should be pointed out that nothing stops a person, clergy or otherwise, from advising victims to report such crimes. The authorities are not limited by the two witness rule and have much more robust forensic tools and investigative approaches than a layperson does.
And, of course, if the general attitude was to report such crimes instead of worrying about tarnishing the organization's image, you could also make it a clear policy that this should always be done. Then, it becomes less of an issue whether the clergy should prioritize privacy over the safety of children.