I agree that freezers were not designed to cycle on and off frequently. They are designed more to keep the ambient temperature well below the freezing point and anything below that really doesn't matter.
However, a fridge is designed to keep the ambient temperature within a range, and their compressors are designed to handle frequent on-off cycles. Think about how many times at 26 cu.ft. fridge's door is opened on a summer day with 5 kids running around. However, this kind of activity is not common with a freezer. You usually open that bad bear up once or twice a day and that's it, possibly less.
Normally in modern frost free systems only the freezer has the evap, and the fridge thermostat operates a duct, allowing freezer air to blow into the fridge. The compressor runs until the freezer is satified, the thermostat powering the compressor is only connected to the freezer. If the fridge requires cooling but not the freezer, there's plenty of freezer air to circulate into the fridge after the compressor has turned off. Eventually the cmpressor will start again when the freezer temp gets too high.
If you have a small mini fridge, there's a freezer box on top that stays at freezer temps. On a wine fridge, they usually have a disclaimer saying something like "Do NOT leave the door open for an extended period of time, or repeatedly open and close the door, as this can shorten the life of the compressor".