pretty much any form of bdsm involves sex. Why are you all acting like prudes? There is nothing wrong with it, it's just unconventional means of getting off.
I don't see anyone acting prude here. Just, I think you don't get at all that there can be something intellectual, or emotional, in that kind of practices. Sex, or getting off, is not necessarily the goal there.
It's like saying that there's no such thing as platonic love and everyone just wants the next orgasm.
I'm not into it myself, but I can understand that there can be something really intense emotionally in it.