When I was three, I had no knowledge of the printed word, did not know how my name was written and thought a pencil was something to scribble all over my parents magazines, etc. How does one expect a three-year-old to know what they are talking about or what they are doing?
The idea is to instill unquestioning obedience and nail them down before they know better and start thinking for themselves. So they start the conditioning young.