Gorillas are an endangered species, and it was obvious that the gorilla was trying to help the kid, but he didn't know his own strength. Gorillas are peaceful plant eaters that have routinely save human lives and in situations similar to the harambee incident. To be honest, I didn't know the race of the child or the parents until black bloggers and journalist made an issue of it, and I didn't care.
Alligators are vicious cold-blooded meat eaters, that look nothing like humans (gorillas are similar to humans in many regards). Of course people will feel more empathy and sympathy for a creature that is peaceful, more human like and has saved humans in the past.
Plus the family affected by alligator attack is indian. There is certainly a lot of racism towards south Asians because they are associated with Islam although the majority of them are not muslims