Jean Cocteau and Francis Poulenc wrote a one-act opera called “La voix humaine” (1958) for a solo soprano, which is a one-sided conversation. There were a few of these as the technology spread and created concern about the surreal, one-sided conversations people over heard.
In the Poulenc the women is the victim, having her last conversation with a man who is dumping her.
Eastwood’s trick is perfect for our era of perpetual campaigning: It creates the illusion of a conversation while silencing the party Eastwood doesn’t want to be heard, then, with his “No, I won’t shut up,” shifts the victim status onto Eastwood. The “one-sided conversation” is probably what many Americans think politics is these days.