I agree that almost all aspects of BDSM incorporate some form of humiliation. I think many people make the mistake of thinking that because something is erotic to them then it cannot be humiliating. Humiliation has a negative connotation to some, so they are unable to see the difference between erotic humiliation and just plain old embarrassment.

Imagine your mother or some other ultra conservative person crawling around wearing a collar and leash. Mine would probably rather die than do something like that while I enjoy it immensely.