That project doesn't clone an API. It uses one. It might be violating TOS, but not copyright.

I didn't know about the Katzer case, but I still see no danger to the FOSS community and ecosystem by the new ruling. All it would do is require developers to clearly specify the license for their APIs. Cloning of proprietary APIs is most certainly not a cornerstone of FOSS today (unless, that is, Linux is in actual danger, in which case I'll change my position).