There's a lot of bad poetry in the world that just follows readers' expectations. I should know, I've written some of it. Unfortunately, I'd suspect that most readers' understanding of poetry lacks that crucial element of subversion, and so an LLM – which mostly just spits out the most-probable, most-expected next token – looks like what people think poetry is.
An LLM would not have created the curtal sonnet form, because it would've been too busy following the rules of a Shakespearean or Petrarchan sonnet. Similarly, an LLM wouldn't create something that intentionally breaks the pattern of a form in order to convey a sense of brokenness or out-of-place-ness, because it's too locked in on the most-common-denominator from previous inputs. And yet, many of the most powerful works I've read are the ones that can convey a disjointed feeling on purpose – something an LLM is specifically geared not to do.
Poetry aims for the heart, and catches the mind along the way. An LLM does not have the requisite complex emotional intelligence, and is indeed a pretty poor simulation of emotional intelligence.
Consider Auden's Epitaph on a Tyrant, which is powerful because it is so suddenly shocking, as it describes something that sounds perhaps like an artist or author, until it very suddenly doesn't, on the last line:
Perfection, of a kind, was what he was after,
and the poetry he invented was easy to understand;
he knew human folly like the back of his hand,
and was greatly interested in armies and fleets;
when he laughed, respectable senators burst with laughter,
and when he cried the little children died in the streets.