Chris,
Sorry for the misinterpretation. Diane Williams seems to be merely putting the idea out for debate as well.
Williams' observation that most people have a balance of left/right abilities seems accurate to me, and most of those with a dominant side have only a slight dominance. Perhaps those who have a profoundly dominant side (from either side), such as Donna and me, are rare and that is the reason we find few with whom we can closely relate.