The reality is that copyright covers verbatim copying. If you read a book and write a review, the term "derived work" makes English sense, but not legal sense. Similarly, if you read the MySQL code looking for magic words to say to the server to get it to give you data, saying those words is not copyright infringement. It's "learning", not "copying".
If anyone used MySQL, I would write a BSD-licensed API just to prove a point. (And to be non-blocking.) But the world has moved on since the Oracle deal...