In this case and context I'd rather see a single gorilla die than a human, but it's sad, and could have been prevented by both parties. I feel like the parent is more at fault, but again like I said, it could go to a jury court to really find that out if the Zoo feels wronged. I doubt they will press charges though unless pressed by the parent at fault here.
A lot of times it takes 3 points of failure for a catastrophic accident, and this is something common in
NTSB work.