Two counterpoints to this unfortunate story. First is several times in years past at the JFK RCC. I have gotten my boarding pass for my first flight and gone to get the additional ones at the RCC. On several occasions they have checked to confirm the unusual routing isnt a mistake. But when I confirmed that yes, I basically am flying around the country aimlessly they always chuckled a bit and said something along the lines of "if that is what you want to do, thank you for doing it with United, we appreciate the business". One said also, "I guess its that time of year again, we get a lot more of these towards the end of the year" with a late December run.
Today at SFO Admirals Club. I arrived from JFK at 12:30 and had a 3:30 flight back to JFK. I checked and the 1:30 looked decent for an upgrade. I asked in the AC if I could get a boarding pass for the 3:30 and get put on the standby and upgrade list for the 1:30. She looked at my itin rather bemusedly and said, "Im guessing you didnt check a bag". I confirmed and she printed out my bp and said I was on the list for the early flight and it looked good but I needed to get to the gate because they were boarding. Nothing but polite assistance. Same with the people at the gate who cleared me onto the last business class seat on the early flight.
Im pretty calm in general and polite to a fault. But if someone had said to me what was said to the OP a lot of people would hear about it, from the managers at SFO to the newspapers. People like this should not be working in a CS job. That guy should be sacked immediately. My guess is that absolutely nothing will be done about it by UAL either.