Do you know that the accident was the "fault" of the parents? It's very easy to respond with understandable emotion, but the facts of the incident need to be established before the lynch mob is set on the boy, or his parents, or even the zoo.
Some people certainly think that it is the fault of the parents for not keeping a steady grasp and a close eye on their kid to trigger the zoos response team to shoot a popular animal dead just because it was a 21st century Jambo incident that took a turn for the "worse".
Critics blame parents, Cincinnati Zoo for gorilla's death - CNN.com
Besides, did people really think that the gorilla was going to kill the kid because he dragged the kid? If the silverback wanted to kill the kid, he would have just ended it there.