The article suggests that as well, the way I read it:

"Actually, the purpose of the software is to recognize whether a special key has been pressed or released. Instead, however, the developer has introduced a number of diagnostic and debugging features to ensure that all keystrokes are either broadcasted through a debugging interface or written to a log file in a public directory on the hard-drive.

This type of debugging turns the audio driver effectively into a keylogging spyware."

Carelessness sounds like a fairly reasonable explanation, simply applying Hanlon's razor. :)