Here’s how I would judge:
If the church member is coming to, and confessing to another church member BECAUSE of their position of authority in the church, then that person should be accepted by law as clergy - since it is their role in the church that elicited the admission in the first place. Since every male is a priest, there is nothing about holding that position that would draw another member to discuss deeply personal and troubling matters with them; as I would go to my pastor in similar circumstances.
Because of the role they play in the church, an LDS bishop most closely parallels a pastor in most other denominations; an LDS priest is simply an acknowledged member of the church.
Every male LDS member is technically a member of the Clergy since they are all ORDAINED priests. Unless the conveyance of the Priesthood means NOTHING (which is what I believe BTW) then a 16 year old priest is as much a member of the Clergy as a 55 year old Bishop. Neither position is paid in the LDS Church and all are technically voluntary. Hence any LDS man charged under this law with failing to report child abuse after another LDS member confesses to them would have this defense available.
Are you willing to admit that the LDS Priesthood is just a lot of fluff and has no legitimate spiritual or legal significance or is it your position that LDS Priests are really "Priests" in the Biblical sense?
Is it just a stupid title to make 16 year olds feel important or are these children really holding some kind of significant ecclesiastical position of authority?