Ranked Point System

Can someone explain to me the logic behind giving 12 points for wins and -24 for losses? You know, besides the obvious answer that Riot wants to make it as difficult as possible to ladder climb? It sure is an extremely discouraging feeling after having a a few wins, only to be set two matches back again after a single loss. Always one step forward then two steps back...I would really like to hear an official response to this.