That's a fair point. I think the real problem is the backswing, which is where you can sway off the ball if you concentrate on getting the weight on to the right foot. Loading into the hip prevents swaying off the ball and actually helps a more complete turn of the shoulders.

I could have added in the original post that, having loaded into the right hip, I do transfer my weight on to the left leg with some small lateral shift in the hips on the downswing.