The difference is obvious, and I doubt they will win here. If you go to confession you are confessing to one person and that person is bound by an oath not to tell ANYONE. The elders have already talked about it openly with the victim's mother and perhaps even more. Obviously it isn't a true confidentiality issue.
I'm glad the Victim's mother is pursuing this instead of just rolling over and assuming the "firm talking to" and the bible is enough to stop this man (assuming his guilt of course).
It is hard not to become irate about stuff like this, regardless of what religion it is. You can't just ignore molestation because you were told in confidence. I think there are some things the sinner needs to STFU about and rot in their own guilt if they don't want it "out there". The idea of being able to confess to molestation, do a penance and move on is really quite sickening.