She almost stopped him from getting into the encloser but unlike the mother of the kid she kinda was also busy and being resposible and watching her own kids.  Also toddlers are usually one or two, three at most.  The kid is four years old that is definetly too old for being a toddler I would say he is a pre schooler.

4 is still toddler. That's a nice made up story. Witness said they looked around wondering whos kid it was. After he fell in people then wanted to go in after him but the witness stop them.

A four year old in no longer is a toddler.

https://en.wikipedia.org/wiki/Toddler

My original assesment was right it is a child between one and three.  Also its not a made up story here is the youtube video:

https://www.youtube.com/watch?v=u3go-JovCaY

Bottom line is the mother of the kid was totally irresponsible or none of this would have happened.

So, the AZA is saying they will require modifications. The designers of zoos are saying it's the zoos responsibility to make their exhibits child proof. But it's the moms fault? Sure. Your original assesment was toddlers mostly crawl... Which was 100% wrong. Your secondary assessment is 4 isn't toddler anymore. Which is also wrong. What does 5T in kids clothes mean and what weight would that child be? 5T = Toddler. The child would be 40lbs+... Show me a 3 year old that weighs 40 pounds and I'll show you an overweight kid

meh I really don't understand how anyone could logically value the life of an animal over a human. 

Logic. We do more harm than good. We are the Earth's cancer. 

That's not logic. That's hyperbole

Is it not accurate? We destroy more than we protect. 

Define destroy... Because we certainly aren't just meaninglessly pillaging the earth in the name of senseless destruction. We create new things from those resources. And things we rely on for survival at that. Even then... How does that put a gorillas meaningless life over a humans? Seriously,  once you and people like you grasp the concept of the purpose of life is simply to survive then we can get past the justified killing of this gorilla

My first assement might have been wrong but my second assement was spot on its a child between one and three years old you might actually want to read the Wikipedita article I gave you a link to you might learn something.  The AZA might say that it require modifications but it couldn't have been that bad since no other kid came even close to entering the exihibit in its 40 year history.  Again this mostly took place because of a irresponsible mother.