"With all parries use the outside edge of the blade to meet the attack, and never the flat. Edge should meet edge."
(sigh) not suprising really. He gives no reason for this - just his word. And I think thats why things are as they are. Someone who is viewed as an authority makes a statement on something they havent researched and the misconception grows.
Because they don't care about killing the other guy like we do.
What they
do care about is how it looks. When you strike edge to edge, both swords are in profile to the audience so that they can see them. If you do an edge to flat, a lot of the time the audience is looking at the edge of one of the swords and won't be able to follow the action.
Our way is for killing, their way is so people can watch.
"A sword never kills anybody; it is a tool in the killer's hand." Lucius Annaeus Seneca 4BC-65AD.