An offense's playbook has a lot more plays available when starting from their own 20 than from their own 1. Since the kicker would be kicking somewhere between the 8-9 yd line and the holder can't change his position too much (without making it easier to block the kick), there may not have been enough room to give the kicker time to hook the ball inside the right upright. I suspect in most cases the kicker either ends up kicking the ball barely wide right or tries to over compensate and ends up kicking the ball wide left. Even a left footed kicker would have difficulty slicing the ball to the left of the right upright from the right hash.