I know this is an old thread but I just got here. Did you read the whole article? It says:
"Understand, this is only true of clubs lofted at 20 degrees or under."
and
"At higher lofts, such as over 40 degrees, the nature of the contact period changes. The ball experiences only the first stage of contact, except this time the increased loft means that the ball never sticks to the club face. Instead, it only experiences a sliding up the club surface. This means that the downward frictional force exerted on the ball is proportional to the surface roughness; a rougher club face creates a larger downward force, resulting in increased backspin."