This joke is explained with a story by Neal Stephenson in his "The Hole Hawg of Operating systems". It's a short, but great read: http://www.team.net/mjb/hawg.html

To quote:

"But I never blamed the Hole Hawg; I blamed myself. The Hole Hawg is dangerous because it does exactly what you tell it to. It is not bound by the physical limitations that are inherent in a cheap drill, and neither is it limited by safety interlocks that might be built into a homeowner's product by a liability-conscious manufacturer. The danger lies not in the machine itself but in the user's failure to envision the full consequences of the instructions he gives to it."