I dunno. That's a "When did you stop beating your wife" question.
Unless you can show me some sort of "proof" this is LLM writing, it doesn't read that way to me. And I read a lot of obviously LLM-generated content. I'm 100% sure it was cleaned up by an LLM, because I don't see any glaring mistakes (grammar, spelling, article mistmatch, etc.). But it doesn't have that "prompt-> article" AI-slop feel to me. And some of the lines, like the ice cream frog being boiled, are things you'd never have an LLM suggest.
IF you can "prove" otehrwise, I'm all ears (eyes).