Perhaps it shouldn't, but under current law it probably would be. Justice Roberts asked a very similar question during the hearing:

Roberts: Let's say someone copies the headings in your brief and they copy the organization in your brief, which sections you put first and how you organize them. Would your argument say that's perfectly fine so long as they write their own text?

Google's lawyer didn't really have a great response to that. He said "no but computer programs are different" but really didn't provide a compelling argument for why.

Can you even create a recipe from scratch after you've learned the recipe from somebody else, will it not always be a derivative work at best, and a copy at worst? Sure, you can add or remove an egg, or change the order or when to add salt or pepper, but an omelette is an omelette.

Maybe, but imagine the original cookbook as a website with hundreds of pages of recipe titles and descriptions, each with a link to the body of the recipe. Someone clones those hundreds of pages, replacing only the domain name in the links. Now is it copyright infringement?

Can designing an API be a different job from implementing a design? If so, then maybe the work product of the designer is copyrightable on its own.