Role playing is when you pretend to be other people, usually with along other people and a format. It is not a name for the trappings of Tolkien novels. Pretty sure that's the joke.
“RPG” or “TTRPG” refer to role-playing games, most often set in fantasy settings. The article is playing off of the fact that role playing as a device can be used outside of those settings to gain insights and mental latticework.