Is API just code.
The article skirts the issue, which is whether APIs need to be available to everyone by saying that APIs are copyrightable, so they are the same as the rest of the code. Legally, this may be so, but as tech people we cannot accept this argument.
The whole basis for copyright law hinges on the constitutional requirement that it must "promote the progress of science and useful arts". It is clear to technology people that open APIs promote progress of science and useful arts much better than having APIs treated as the rest of the implementation. APIs are created for the sole purpose of isolating the copyrighted implementation from the open outside environment, they just cannot be considered the same.
The problem is that copyright law is antiquated, not only does it fail to "promote the progress of science and useful arts", it is actually used to prevent the progress of science and useful arts, and is thus essentially unconstitutional. However, vested interests and technological ignorance by judges has prevented the concept of copyrights and patents to be correctly applied to the software industry. By "correctly", I mean in such a way that they "promote the progress of science and useful arts" instead of achieving the opposite effect.