Honestly? Hell if I know.
I don't claim to have "come up with" or "invented" the term, although that language has been used elsewhere. For me, "coining" is more about framing the term than inventing it - as the first "critic" to use the term within the official discourse around the show, that became the avenue through which other critics picked up the term, and it seemed to enter into a more popular discourse. While "popularize" is therefore perhaps the better word, "coining" is the most common choice by journalists who are writing about it (and who come to me through those other critics), and that's ultimately out of my hands.
Also, as others have pointed out, how do you invent a word that's just adding an "s" to another word? While I don't see myself as the inventor of the word, however, its association with me through these various outlets has led me to take some sense of ownership over it, which has led to some confusion over its origins (which isn't helped by the selectivity of journalistic accounts).
