I'm conflicted here. Your first paragraph initially opens the loophole "but AI art" could be the medium in which the artist is expressing themselves. So poor prompting could be beautiful too, in a way. I'm sure photographers of the past felt this way about software post editing when that became popular.
The results may be good to many viewers but apalling to anyone who can tell the difference. If the results don't matter, does it matter if AI slop is "bad"?
The prompt may have been beautiful, and the process of learning and finding the right tools (i.e. choosing the right model) is akin to the struggles of any artist in learning their craft.
/devil's advocate