I can't imagine the "seal of confession" applies to all of this knowledge. There is likely a good amount of old-fashioned criminal cover-up going on there.
Not that I particularly care about religion, but I still don't like the precedent regarding confessionals for the same reason I mentioned last year: it creates incentive for the criminals in question to avoid saying anything at all. I'm not convinced by this "guilt was absolved thing", as I suspect most offenders continue the sexual abuse at some point. If that premise holds then seal of confession vs not would be neutral, not something actually contributing to the systemic problem.
The priests/higher ups being criminal offenders themselves is a bit tangential to the legal question at hand but also the bigger problem.