Claude Lanzmann is in a bad mood. The director of “Shoah” is here to publicize the 25th anniversary re-release of that classic documentary and, whether he is jet-lagged or bored or subject to the cantankerousness that frequently befalls a man less than a week shy of his 85th birthday, he is in a bad mood and making no effort to conceal it.

Film festival programmers frequently feel themselves caught in the middle between dueling imperatives. On the one hand, it is important to show the best films available within the scope of the festival. On the other hand, it is also important to have those films spark a dialogue, a conversation that will continue long after the sound of applause has faded away. When the film festival has an extra-cinematic agenda, that two-way tug-of-war becomes more complicated and sometimes even painful.