I got this far:

Animals inhabiting their evolved, ancestral environment are healthy — by default.

or they're dead. Because, in the wild, animals die. A lot. Especially ones that get at all unhealthy. Whereas we humans - social creatures who have resource abundance, knowledge, and skill to be able to carry our sick and unhealthy well past a time when they'd have died in the wild - die less. At least, from being unhealthy. We don't always use these resources wisely, especially in some countries, but from premature births, to congenital diseases, to severe cases of autism, these humans have a far greater chance of surviving infanthood than any such defects in wild animals. Heck, merely being the smallest of a litter is enough to doom you, in the wild.

The article might have been well-informed and factual, but starting with such an absurd premise, I couldn't maintain interest long enough to find out.