I never paid much attention to it, but that style also pervades goodreads. But in that case, the style was there before LLMs. Many people seemed to think reviewing a book consists of writing a summary of the first chapters. It's the template you get taught for your first book reviews in secondary school, I guess, and it does work: such reviews (not only on goodreads) get upvoted. But why? Perhaps because it saves the upvoter the trouble of reading the book or article?