Why Illiteracy is Tolerable

I know that there are a miriad of campaigns out there trying to nip illiteracy in the bud. However, I think that there can be an age when it's too early to teach a child to write. This would be the age where the only concept they grasp is: "Hey this is a pretty cool little stick!!" Despite the fact that B is actually smart enough to spell his own name and write out the alphabet, he recognizes that writing utensils can be used for pleasure as well as educational purposes. As evidenced by the permanent marker on his door.