Why does Winston feel that the man sitting next to him in the cafeteria is not A real human being but some kind of dummy?

Winston feels that the man sitting next to him in the cafeteria is not a real human being but rather a "dummy" because of the man's lack of genuine emotion and his mechanical behavior. The man's mannerisms and expressions appear rehearsed and devoid of individuality, leading Winston to perceive him as a product of the oppressive society that suppresses authentic human connection. This observation contributes to Winston's growing sense of alienation and his quest for true humanity in a dehumanizing world.