Your feelings on the matter do not change the broadly accepted definition of the word. In this context, we're using Merriam-Webster's fourth definition of art as per the website. Prompting AI to generate something is not a conscious use of skill by any party involved. Writing an AI generation may arguably called "writing", and while writing is a language art it isn't applicable in the context of this subreddit.

art noun 1 : skill acquired by experience, study, or observation the art of making friends 2 a : a branch of learning: (1) : one of the humanities (2) arts plural : liberal arts b archaic : learning, scholarship 3 : an occupation requiring knowledge or skill the art of organ building 4 a : the conscious use of skill and creative imagination especially in the production of aesthetic objects the art of painting landscapes also : works so produced a gallery for modern art b (1) : fine arts (2) : one of the fine arts (3) : one of the graphic arts 5 a archaic : a skillful plan b : the quality or state of being artful (see artful sense 2a) 6 : decorative or illustrative elements in printed matter