I didn't think anyone here would question the validity of a copyright of a COMPLETED work, such as an entire software library. What is at issue here is the patenting and/or copyright of an API, which is much like the patenting or copyright of a "general idea".
Patents are supposed to be VERY specific and apply to a specific invention. Copyrights are for written works, etc. and "fair use" allows a portion of that work to be used by others without paying royalties.
So the real debate is, can you patent an API? (I believe it is too much "a general case" and not specific enough to a specific invention for a patent to be granted). And can you copyright an API? (if the API were for a specific copyrighted work, such as a software library, and the library itself is copyrighted, then the API, a portion of that library, is subject to "fair use").
Any restrictive deviation beyond what I just mentioned would simply be a FEEDING TROUGH for BOTTOM-FEEDING L[aw[YERS. And you know the L[aw]YERS are the ONLY ones who WIN this kind of CRAP!