Reporters are supposed to report the truth. In this case, many are not doing so.
If you choose to believe those who are not reporting the truth, you will draw faulty conclusions, and you have.
In this case they seem to be trying to sort it out. All of the issues were coming up....parental supervision, adequate safeguards, other alternatives, was the child in danger etc.
The more I think about it, the zoo is at fault. It's a "given" that a lot of parents are irresponsible. It could also easily happen with a field trip. There should be some kind of barrier or enclosure that stops the animals from getting out and people from getting in. Why? The zoos have a primary obligation to keep the animals safe and secure. I'm not at all comfortable with a situation where the animal had to be killed when it wasn't at fault.
I think of the zoo near here. There are situations where they assume the animals can't get out. If provoked, I'd wager some of them could. But a lot of those habitats are such that people could get in.