I agree the gorilla had to be killed but the parents should face charges as well.
Not I.
When kids get a hold of a gun and kill themselves or another person, I think the gun owner should be held responsible for negligent homicide ... and do serious time, even if it was their own child who died or was injured. And if they have other children serious consideration should be given to removing the child from the home.
Personal responsibility is not just a buzz phrase. You either believe in it or you don’t. I find mostly people do not believe in it despite what they say.