Derpy started out as an unnamed background pony who was accidentally given googly eyes by the show's animators, but fans gave her a name and a backstory -- she delivers mail and loves muffins! -- that made their way to the show earlier this year as a nod to Bronies.
But the My Little Pony writers retroactively took away Derpy's name and goofy voice, causing an uproar among fans, who all had their own theories about why the change had occurred.
When she was asked to name the pony "Derpy," she didn't realize that the term is sometimes used as a synonym for "retarded," a slur that hits close to home for her.
Now, you have to realize that reading that made my heart sink. My son Soren (of Soarin' fame) is severely disabled. We do not use the word 'retarded' in our house because it really has become an offensive slur. And while I knew that it was only a minority of people that defined 'derpy' this way, it still upset me that I was the writer that put that name out there.
Although Keating didn't personally make the decision, she thinks Hasbro "weighed what was best" for the My Little Pony brand and retconned the potentially offensive name out of the show.
The Brony community was happy to finally have an explanation, and fans say "peace and order" have been restored to Equestria.