I find the statement their about making white wool confusing. I tried bonemeal with non-white wool and it was unable to do anything regardless of configuration. I haven't tried making white wool from bone meal and white wool because that would be pointless and stupid. If that's the case, the wiki should clarify and say
"Bone meal is used to make white wool by crafting one white wool block with bone meal above it. Other colors of wool cannot be dyed white, so this is fairly useless."
However using dye on sheep works and is funnier anyway...
Yes, my guess is that it's an oversight -- white wool is the only colour that can be dyed to another colour, thus the redundant "white wool + bone meal = white wool" formula. I believe, however, one can use bone meal to dye black or grey wool white while it's on the sheep.