There is a difference between objections to style and objections to clarity and conciseness. My complaint with AI isn't that it's not formal enough, it's that there's so much bullshit and so little content in AI-generated blocks of text.

"Slop" is generally meant as a derogatory label against anything in the AI vernacular - it is not an objection to clarity, it is a repudiation of the idea of using AI for writing at all.

It's the same tired game we play, as a society, any time a new writing style enters the mainstream. That game goes back to at least Shakespeare's era, where our illustrious bard was called out for his tendency to make up words ("fashionable" being, I believe, an actual example of this?)