Genre terms exist to prime expectations for players.
What a ridiculously self-centered claim. Genre terms (and other categorizations) exist because language users use them to make things easier to communicate about. I can only imagine the author of the article going: “Well, actually a tomato is a fruit, not a vegetable” when talking to a chef about gazpacho, or “a penguin is not technically a bird because it doesn’t fly” when someone says that a penguin is their favorite bird.
MFer needs to learn about cognitive categorization, prototype theory, etc. It doesn’t need to be 100% the same within a category — then the category is too specific and is absolutely useless — it just needs to be similar enough that most people (that aren’t necessarily experts in the subject) understand what you’re getting at.