It's all relative. Fracs and dms to the arms/legs will still give points, but only for the value of the frac or dm. I.E. 2 or 3 points, the same as a full on nut shot gives. Relative to a rib shot, a shin kick is not very painful. it's meant to wear the opponent down over the course of a fight, like muay thai fighters do, not cause massive instant pain. Considering our belt level equivalents in real life, our toris should be able to take some leg shots without it hurting them too much at all.