I don't know the real answer, but I suspect it related to the relatively low moisture content of cheese, compared to many other things we smoke.
Moist, soft cheeses, such as Brie or mozzarella age and the smoke flavor mellows faster than drier cheeses, such as sharp cheddar.
High moisture content meats, such as poultry, seem to absorb smoke flavors faster than other meats, so we apply smoke for a shorter period of time than we do for pork or beef.