NEW YORK — He is a close-talker and a loud-talker whose voice can be the verbal equivalent of fingernails on a chalkboard. David Stern has called his behavior “routinely despicable,” and on more than one occasion he has commandeered the post-meeting news briefings to incessantly spew vitriol at the NBA owners with whom he has been butting heads. He is Jeffrey Kessler, the lead outside counsel for what used to be known as the National Basketball Players Association, and he is