Why does Gulliver being to view humanity differently

In part four, the author meets the meets the Houyhnhnms. They are an enlightened species of horses that hold none of the vices and disagreeable traits of humanity. After spending time with the Houyhnhnms, Gulliver begins to see the folly of humanity's reckless society. The Houyhnhnms seem to underscore people’s greed, corruption, and short sightedness.