If people honestly think that animals are only kept in zoos “for the pure amusement of humans”, then I’d like to know what they think of the newfangled wireless that Mr. Marconi just invented.
Zoos today aren’t in the entertainment business as an end in itself anymore. Their primary purpose is education of the populace and preservation of endangered species. For example, if not for the Los Angeles and San Diego Zoos, the California condor would be long extinct. Instead - thanks to the fact that the remaining small population was in an environment where they could be truly protected and cared for - they are now back in the wild and signs indicate that they are taking the first steps on the road to recovery in areas where they haven’t been seen for nearly 100 years. That would not have been possible without people having seen these animals in person and being moved to give money as a result.
Realistically, if Harambe had been born in the wild, he would most likely have been shot by a poacher long before now and served up as bushmeat somewhere. In a modern zoo, the animals aren’t captives - they’re ambassadors.