I can't say I entirely disagree with you, you definitely make some valid points. And the very fact that men are willing to pay money does speak to the power the women hold sexually, but the fact remains that they're being paid to be used and to service men. They're being paid to submit. And while I'm sure there are plenty of women who have no problem with that and some who even enjoy it, just as there are those who enjoy being slaves or submissives, neither at all fit Selina to me. In my mind, for Selina it's Domme or nothing.
I did mention her being a madam / proprietor because I think she'd probably feel much as you do about other women doing "submissive" sex work, and be inclined to benefit women in the industry by providing them a safe place to work. Nor do I think she'd look down on them, per se, and certainly wouldn't treat them poorly in any way, but she would probably harbor a personal distaste for it and never want to do it herself.
To clarify, her attitude towards conventional prostitution is probably similar to my attitude towards sex with men -- I find it personally distasteful and something I'd never do, but I understand there's lots of people who quite like it and I'm obligated to respect their choices.