True, rape is about power. It can also be an opportunistic crime; a person inclined to rape may decide to exert that power moreso if an opportunity is afforded him. It's going to be a lot easier for a potential rapist to commit his crime when there are vulnerable people in a vulnerable situation. Of course plenty of men and women get loaded together and rapes don't occur. That is because most men are not rapists.
There is never an excuse for rape. However, it is a very good idea to not place yourself in a situation where you can be victimized. I fail to see how pointing this out is blaming the victim. When I was a teenager, all the girls were warned not to help out the nice guy with the cast on his arm load his boat onto his Volkswagen. I don't recall anyone blaming Ted Bundy's victims for his crimes.