I think its important to comment that the rape fantasy is not part of BDSM role play. BDSM is about a man or a woman, putting another man or women through a series of physical challenges to help the former person grow and learn more about themselves. Master or Dom's are supposed to be like mentors to the submissive persons. Both the master and the sub can get physical and sexual pleasure from pain or inflicting pain on others, but thats not the main point of BDSM. People also can play around without being subs or doms. Lots of people like doing wax play, bondage, biting, cutting, pulling hair, etc during sex. This is more like sex play sometimes role play, but not real BDSM. In real BDSM there is rarely any actual intercourse. What is depicted in porn films as BDSM is normally just rough sex or kinky sex, not two BDSM partners who are in a relationship.
I have no idea where you're getting this from, but that's not the "point" of BDSM from anyone I have heard from.
Where are you getting this from?
Maybe that's the way a few people approach it, but that isn't the way everyone does.
As Heather said--there's a large sphere that BDSM includes, and to say that it only includes what you're saying is really incorrect.