Even if we consider Duchamp's creation an outlier - one may say if it were created, say by some random plumber, instead of Duchamp, this urinal would not be as important of art piece as it would be if made by Duchamp, there is a plenty of other artistic niches - say DJ or an interior designer, where the author does not create a thing by themselves, just combine existing items, yet we judge the art piece purely by aesthetic merit, irrespective of the who exactly was the author.

I mean it is as simple as saying - here is my statement, it was generated by an LLM, but I had prompted and edited it, or even simply chose a single generation out of 500 and this conveys my feelings and therefore is art.

>yet we judge the art piece purely by aesthetic merit

And that's the central conflict here. That "we" might include you, but it doesn't include me. The question of "Why?" is central to art for many of us.