AP is 100% art, although it requires technical skills, but many other arts also require them.
So is "regular" photography. The final product (whether astro or not) is a result of composition, subject choice, lighting choices (yes, even with stars!), and all of the subjective choices made in post-processing.
To get the best result, it takes technical skill -- whether astro or not. In "regular" photography, if you don't understand lens performance, effects of aperture and shutter speed settings, light theory, color theory, the technical ins and outs of multiple flash systems (and communication between units), noise levels, and the technical aspects of post-processing, you aren't going to get good results. But it's still art.
By the way, my point in the other thread was that AI/ML can and more and more will assist with/take over some of the technical parts, and leave us more able to focus on the artistic parts. Regular photographers didn't, in the past, have autofocus -- learning the skill of focusing with a ground glass was a technical skill that has now almost entirely been automated. So now the photographer can focus (pun intended) on composition and framing and color and light and not worry so much about focusing. In AP, "smart" systems already help us autofocus, we have flat wizards (to assure good flat exposure levels), automated sequencing, GOTO, etc. etc. etc. Adding more "smart" systems that can analyze images and decide on the best darks/flats to use, choose processing steps to minimize noise, etc. will do the same, let APers spend more time on the art of their work.