At least that's a short route. A guy did this LAX > ORD a month or so ago. Several people asked him to turn it off and he insisted he does this all the time and no one complains. I was a few rows up but while disembarking I told the guy "you're a nightmare" and he looked at me kind of stunned at which point I followed with "there is no chance in this world that is the first time a stranger has said something like that to you, get used to it."
I'm so glad you said something, even at the end of the flight.
The policy written in each month's issue of "Hemispheres" says that ear phones must be used at all times. I have pointed this out to both other passengers and FAs (to show to passengers) - which has always worked (so far!). It is always on a page toward the back where the food, entertainment, terminal maps, etc., are printed.
JK-SFO