You may want to turn in your FReeper card. It was an animal. Ascribing human attributes to an animal is just plain wrong.
The gorilla did not know its name. If it had a daily calendar, it would read, find food. Next day,find food, next day, Find food.
It has no emotions, It has no specific intellect, nor was it pining for the jungle in Africa.
When the boy fell down in the pit, the gorilla opened the calendar in its brain that said Find food.
A bullet to the head was the only solution. Thee is no justice needed.
If it was predatory it would have been a killing, and the boy would have been dismembered in seconds.