Your mention of CYOA books calls to mind what was stated in the article, namely:
…its central focus on player agency, the game’s inherent spirit of playfulness and the variability of player experience.
All of those things also describe CYOAs, but I doubt anyone would call them a game either. With the possible exception of the Lone Wolf series or Fighting Fantasy.
It’s a question of medium really. People are used to calling everything that uses a computer or game console to deliver an interactive experience a “game” even if it really isn’t.
I wouldn’t call a haunted house a play even thought it shares many outward elements: a cast, costumes, props, sets, etc.. It lacks the essential elements that would be used to typically define a play just in the same way that the opposite will never be true. Calling one or the other by the incorrect label would simply be a hassle for everyone and serve no legitimate purpose. It’s the same reason that a website devoted to films doesn’t typically bother to discuss statues. It’s not to imply that they are an inferior or inappropriate art form, but merely that they are not films and do not benefit from being discussed as films or belong in a forum typically devoted to the same.
Experiences like this are relatively recent and they have evolved around the gaming community, in many cases being modified out of software intended for use in games, but this alone does not make them games. The terminology hasn’t yet been defined and the nascent community hasn’t coalesced yet.
Trying to refer to it as a game, discuss it as a game, or promote it as a game is simply doing a disservice to both communities.