You have to be kidding ? If you take the ground off the battery,you can ground power yourself under the car when removing the starter..by removing the positive AT the battery,you have no way to ground power anywhere under the car
If you take the ground (or the positive for that matter) off the battery, there will be no power to anything.
Disconnect ONE of the battery clamp leads and the car is dead electrically.
The ground clamp is the one disconnected usually in case the wrench slips and will cause sparking, which is not good around a battery that emits hydrogen gas as a byproduct of charging.
Think about it.