Why blame him ? He knew it wasn't going to handle it. If the guy persisted in saying it would, sometimes it is easier just to do it, show him how wrong he is and then watch him boo-hoo about how his truck is now a pretzel. And if it did handle it , well one less load to the dump.
Even if he had nearly centerd it and only 10% of the weight was on the PU bumper, how well do you think it would handle 1000-1500 pounds of tounge weight ? What are the chances of it being all coupled together by a 1/2 grade 3 bolt in the reciever or a 1 7/8" ball in a 2" hitch ? Oh YEAH ! I want to see that last very long on any kind of road around here.
My opinion , the owner got off lucky with a bruised ego and a tweaked frame to remind him not to get greedy. His Insurance Company ? was even luckier that day.