Imagine if writers were able to copyright phrases -- short combinations of common words. It would very soon lead to the situation where it became impossible to communicate in writing at all.First of all, you don't "copyright things", other than by creating it. And copyright law doesn't say "well, a work has to be at least N words large". Yet, noone has to worry that if they write down a short phrase they are infringing a copyright, even if someone else has written down the same phrase before them. Yet, they aren't free to copy an entire book.
Now, if APIs were copyrightable (and let me make it clear, I do not have the opinion they should), why should they be treated differently? That is, one shouldn't have to worry about int add( int, int ), but from that, it doesn't imply you can copy a large API like Java.
My point is no more than "I don't think it's obvious that APIs aren't copyrightable". And the mere fact there was a court case, and it wasn't thrown out as frivolous makes me think I wasn't the only one thinking it wasn't obvious.