Characters
You talkin' to me? You talkin' to me? You talkin' to me? Then who the hell else are you talkin' to? You talkin' to me? Well I'm the only one here. Who do you think you're talking to? Oh yeah? Huh? Ok.
— Travis Bickle ‧ Taxi Driver

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The speaker repeatedly demands to know whether someone is addressing them, then reasons that no one else is present, so the words must be aimed at them. The tone escalates from challenge to bravado, ending in a deflating 'Ok.' It reads as a confrontation with no visible opponent.
Context reviewed