I have no clue as to how it all works out.
But I know this: I for one appreciate Bondage and Discipline themes but not Sado Masochism. I believe those that appreciate BD are ones who trully believe in trust and respect. From both the Dominant and the dominee. For the dominee it is a conception of giving away a part of your freedom of mobility to gain freedom to your desires. Things that you want that may seem too frivolous for you but that you can readily accept because of the bondage imposing 'no choice'. Making decisions is also something that some people fear, and that in a way frees you from that. It is also soothing to be held tight, and bondage helps in that regards.
As for the Dominant, it is compassion to the dominee that creates this bond. Perhaps not as much the feeling of ownership over the dominee but but a strong chain link between the two...

My two cents, probably far off.