I think that John stated he views the ball above his feet as the more powerful stance, which is why he thought it would frustrate lefties. It would indeed frustrate a lefty that played a draw, I would think.
As a lefty that likes to play the ball right to left, nothing confounds me more than the stance John prefers. When the ball is level or below my feet, I can start the ball on the right side with confidence. When I get on a tee box that only leaves me with the option of the ball above my feet, then I just aim at the middle and hope for the best. I usually miss left or right, but it isn't predictable.
It sounds like John and I would be happy on the same tee boxes.