First person movement animations are incomplete - Why?

There are four ways that you can move forward in a standing position in RS2:
(1) Walking
(2) Running
(3) Sprinting
(4) Melee charging

For (1), (2), and (3), your weapon sways convincingly.

But for (4), your weapon does not sway. It does not move a millimeter.

Why were weapon sway animations not included for melee charging in RS2?

In my opinion, the lack of weapon sway during melee charging is inconsistent and looks unfinished (you just glide along the ground).

First person movement animations are incomplete - Why?