By that logic WINE shouldn't be allowed to exist either, since it copies Windows' API.

Copying APIs is strictly necessary for interoperability. Allowing APIs to be copyrightable encourages monopolies by legally prohibiting newcomers' software from being compatible with their competition.

It'd be like if Microsoft were allowed to sue Google Docs and Libreoffice for making their software able to open Word documents. (Except in this case the "documents" are source code.)

I'm not sure how WINE works. But I just don't see that being the case. All WINE has to do is capture the API calls and transform them into a different WINE API call that ends up performing the same function and then proceed with zero copyright issues.

> All WINE has to do is capture the API calls and transform them into a different WINE API call that ends up performing the same function

How can it "capture" the calls without knowing what it's capturing? It has to know that there's a windows API function called "CreateWindowEx" that takes particular parameters, otherwise how could it possibly "translate" it? And the fact that CreateWindowEx takes particular parameters is precisely the API.

Of course the implementation of that API will be different in WINE, just as Google's implementations of the Java API are different from Sun's (aside from the 9-line rangeCheck which is a separate issue). In fact it would be fair to describe what Android does as "capture the API calls and transform them into a different Dalvik API call that ends up performing the same function".

> All WINE has to do is capture the [Windows] API calls

So... you're saying it needs to implement the Windows API? If APIs are copyrightable, then that's a violation of Microsoft's copyright. You've included a copy of Windows' API in WINE.

Interoperability trumps copyright IMHO.

Unfortunately courts don't pay attention to your opinion. They only pay attention to grumpy old codgers who don't really understand technology or innovation. They only understand precendents or long ago useless decisions of previous courts and the pragmatism of someone raised on thoughts on computers and ideas of fairness from the 1950s.