I think that sometimes it feels less frightening to blame someone -the zoo, the parents, perhaps even the gorilla — rather than face the scarier reality : terrible accidents can happen to children , even children of good, loving, and very watchful parents.
It is convenient to forget that somehow the mother managed to keep her child alive in his earliest and most vulnerable 1st years of life. He did not choke to death on a swallowed button, shoot himself with a gun found in a drawer, get kidnapped by a stranger, run into the street and get killed by a car.
And for many years the barriers to the gorilla enclosure kept children from entering the gorilla habitat. The zoo officials believed they had protected the public as well as the gorillas.
But neither the mother or the zoo officials could perfectly foresee every possible danger, every vulnerability in the enclosure . They should not be shamed for that. Humans are imperfect and life is indeed full of risks for children — usually small, but sometimes large ones- that can not always be foreseen or prevented.