It's because recipe sites were already ad farms leveraging SEO to churn out garbage and AI just means you can do an even larger volume. Even without "AI" it's why most "[x] recipe" search results give you back incredibly formulaic pages where they tell you a pointless story about their grandpa loving beans or whatever and hiding the actual recipe at the bottom. Most sites were just farming ad money with empty shlock. AI is great for amplifying farm sites because the quality of the content was never the point.