The real reason is because recipes consisting of just the list of ingredients can't be copyrighted, but the articles and all the other stuff are copyrightable.
I don’t see this. If somebody’s scraped just the recipes from all these long winded sites, I’d be thrilled! Adding the extra nonsense and narrative doesn’t prevent that.
A couple paragraphs ought to be enough to make it copyrightable.
Ingredients lists and basic instructions ("place potatoes in boiling water") are not copyrightable. Only the additional text is copyrightable. This has long been a 'problem' for cookbook writers and chefs. Unlike cookbooks, blogs have no particular constraints on how much text they can add, and as pointed out here, perverse incentives to add lots of extraneous material.