I agree the zoo had no choice, the could not take chances.
However, to me it looked like the gorilla was trying to protect the child. Perhaps it was dragging the child to a more secure location. We won’t ever know what it was thinking but there is a reasonable chance that it was not going to hurt the child. There was also a reasonable chance it would have hurt the child. So the zoo had to err on the side of caution.
The villians here are the parents.
There are no parents involved, just a single mother and probably 3 different baby daddies...
Gorillas are often given novel items to keep them from being bored. These items often contain treats. These items are often slammed around a great deal as the gorillas explore their characteristics and figure out how to obtain the treats.
It is unlikely that the gorilla saw this child as anything other than a novel item and was quite surprised and agitated by the loud reaction of the crowd. Stop anthropomorphizing, the child was in serious danger.