There is nothing in the way our brain is wired that makes us prone to enjoy bondage, pain and subservience. In fact, if you asked a psychologist, he would probably tell you that this sort of thing would be a telltale sign of a addled or deranged brain. However, since I have dealt with that in previous posts, I'll move on from there.
I also agree with Bruce and think it just might be an acquired taste. Something read about, experimented with, tried and tested and then processed as a likable form of play and living.
However, I'm not exactly sure as to the distinction made between learned and acquired, as they seem to be the same thing to me.