Yeah, the title of the article is pretty poor. It kind of sounds like someone who was promoted from a developer to something else, rose to the level of their incompetence, then reversed the promotion to go back to doing what they enjoyed.
This person was not a developer previously, so I don't understand how they were "demoted." Other than management > individual contributor.
What really happened was they changed jobs to do something they found more fulfilling. Which is great, but if I decided to change careers to building furniture, I wouldn't say I "got demoted to making furniture."