The movement of the knight
The 2/1 "L-Shape" explanation is simply a convenient way to teach the Knight move to beginners. Whether you explain it as "L-Shape", 1-step orthogonal and then 1-step diagonally outwards, or (as you put it) "/" direction, the destination is the same.
The concept of "jumping over pieces" serves as mere clarification. Unlike orthodox pieces which move in a predictable straight line forward, backwards, sideways or diagonal, the Knight's 2/1 maneuver can't be hindered by any piece thought to be obstructing its path. Newcomers will obviously wonder about this, and so "jumping over pieces" nicely answers their unverbalized upcoming question.