It seems GS replaced license headers from files with their own license. Painting with broad brush strokes here, is stealing from a thief still stealing?
After considering that some more, it seems like the court could (and maybe should) have ruled that it was simply a misunderstanding of the open-source code's license.
It seems like a waste of everyone's time to even pursue a case such as this after it's determined that the person didn't have malicious intentions.
Could the owner of the modified code successfully sue Goldman Sachs?