Well, designing an API is not simple, but actually providing code for that API is the REAL stuff. Personally, I believe, that if someone has reimplemented some API in a better way, than the original author, then this someone has more rights for profit, than the original designer of the API.
If you think about. You get an API and the implementation that does not suit your needs. Now you go ahead and replace part of the package, so that end result suits your needs. Why should you owe something to the package creator for your own work? After all, one doesn't owe anything to Oracle if one writes a program using Java. So why should anyone who created interpreter for java owe to Oracle?
Following the logic of Oracle, we should put Copyright event on the idea of using binary code for digital computation and demand revenues from all hardware producers since they use the same API. Intel then may demand revenues from AMD for reimplementation of their assembler and so on.
I believe, this is nonsense. Oracle just has too much money, so they can waste it on lawyers :)