That we have repeatedly had long standing affairs with black is not in dispute. From the Renaissance Spaniards getting the whole to Europe to fall in love with black clothing, to the nearly obsessive blackness of Victorian apparel, to the current inundation of black throughout the ready to wear industry, we have never been able to stay away long from the siren lure of black.
First of all is the truly profound effect that the color has on our psyches. It is a hard wired part of our response system. Black equals night to us, which in turn inspires unease, and fear. We cannot see in the dark, so we are limited in a way we find uncomfortable. Since we are creatures who process massive amounts of visual information constantly, not being able to see well would of course disturb our equilibrium. The unknown irritates the monkey brain that exists in us, we cannot know if there is reason to be fearful, but we cannot entirely banish that from our thought process.
The connection to sex is one that instantly goes into edgier territory, because the feeling of discomfort, or fear we get when we see black, associates with sexual acts that may be painful, or extreme. So it is no wonder at all that the predominating color choice for gear in the SM/BD realm is black. And when we make that black clothing in leather, animalistic, and militaristic associations get layered onto it which amps up the perceived danger, and the fascination.
Our motivators for being so in love with black include, especially these days, it's association with depression, and sadness. For many people, living in our precariously teetering world, black is a physical manifestation of the unhappiness they feel with regard to the direction our culture is going in. They are expressing their angst silently, but potently.