It's not a cut of meat though.
There are good reasons why they'd be keen to cook chopped meat for longer. Unlike a steak, where you get to destroy any surface bacteria by searing, the outside of the meat will have been mixed through the entire burger. Not too much of a problem with good food hygiene - but definitely more risky serving rare burger than rare steak.
I understand that, however, the USDA considers 160def F. to be safe. I rarely cook any meat besides poultry any higher unless it is asked for that way.... In fact, I usually pull meats from the heat at a temp closer to 150deg F. and allow carrying over cooking to bring it up the additional 10deg while the meat rest. I've never been sick from the food I've prepared. Of course if the meat is older it would likely benefit from further cooking.