If I remember correctly; I could be wrong though, but I believe that Hokuto Shinken was supposed to be taught to few, and those failures who didn't succeed had their fists sealed. Small gripe, based on poor memory though. I mean look at the last generation of Hokuto Shinken! Three! Well technically Ryu is the last, but you get my point if you're an HNK nut.
Nice to Souther, and also his notion of Anti-Love as well, though he too doesn't wholly dedicate to that in the very end. His Mausoleum technically is made for love's sake if you think about it.
Love is at the core of HNK, ever and always.