There is also the conservation role of zoos as a way for the general public to appreciate and experience nature. I mean as corny as it sounds getting to see animals that need protection face to face is also a pretty important when it comes to conservation. It makes an impression on kids, especially, who will grow up wanting to work in conservation etc.

I think the article's emphasis on more humane zoos is important, but most modern zoos already try to do this as much as possible.