If it was about sex, there are $10 prostitutes. And as you yourself pointed out, there are other ways to get gratification other than forcing a woman.
And as I have also pointed out, power is itself an aphrodisiac. You can’t rape a woman without getting an erection, although other forms of sexual assault can be done. I just can’t call them “rape”, regardless of legal definitions. They don’t make one pregnant.
When you look at the fact that BDSM pornography is so very popular on the Web, you have to realize that power is a very important part of sex for many people. People who may not be rapists.