Copyright does not cover ideas and information themselves, only the form or manner in which they are expressed. The argument is the implementation of an API is the expression but the API is merely something akin to the table of contents. It's a description of the thing but it isn't the thing itself. This view seems pretty logical to me.
It doesn't necessarily matter that something is an act of creation -- nearly everything is -- that is necessary for copyright but it isn't sufficient. Your assumption is that any intellectual exercise, no matter have trivial or damaging to the commons, deserves protection. But that is neither the spirit or the letter of the law.
Also, this really doesn't have anything to do with open source and everything to do with interoperability. Open or closed source, copyrights on APIs would lock out entire classes of software that we take for granted every day.
It doesn't necessarily matter that something is an act of creation -- nearly everything is -- that is necessary for copyright but it isn't sufficient. Your assumption is that any intellectual exercise, no matter have trivial or damaging to the commons, deserves protection. But that is neither the spirit or the letter of the law.
Also, this really doesn't have anything to do with open source and everything to do with interoperability. Open or closed source, copyrights on APIs would lock out entire classes of software that we take for granted every day.