I have dug many holes, and have been in many holes. If there is a rock in the bottom, it is not a part of the hole, but the area that defines where the hole is, it is a part of the ground. Being in the hole, the only thing I can truly remove from the hole is myself, and all I have done is increase the air volume, and decreased the me volume inside the hole. To make a hole larger, I still argue that you must remove material from the edges of the hole, not from the hole itself.
Surely that comment is completely incorrect and misguided? Have you ever dug a hole? Climb in one sometime and try to removing something (anything) from it and see if it get's bigger.
If there was a rock in the bottom of the hole and you removed it, the hole would get bigger. Nothing more complicated than that.
Definition of hole: (from the internet) A hollowed place in something solid; a cavity or pit: dug a hole in the ground with a shovel.
To make a hole bigger, you must remove more of what is solid, not remove the hole. If I take away from a hole in my pants for example, I am mending, making the hole smaller, not larger.