I'd say it comes under the 'instrumental rationality' heading. The chatter was clearly bothering the writer, but - irrationally - neither he nor the others (bar one) actually got up and said anything.
The passage states that he'd already spoken to them twice.
...Not long ago a couple across the aisle from me in a Quiet Car talked all the way from New York City to Boston, after two people had asked them to stop. After each reproach they would lower their voices for a while, but like a grade-school cafeteria after the lunch monitor has yelled for silence, the volume crept inexorably up again. It was soft but incessant, and against the background silence, as maddening as a dripping faucet at 3 a.m. All the way to Boston I debated whether it was bothering me enough to say something. As we approached our destination
...but why wait until they'd almost gotten to Boston?
"This is how it sometimes works", I would have said. Anything more starts to sound uncomfortably close to "the lurkers support me in email."