never heard or thought about this before, but it kind of makes sense for a dating app. its one of the only levers available to them to attempt any sort of balance between user genders. it sucks for everyone (including the users) if the male:female ratio is like 20:1 or whatever.
i would rather pay a couple of extra dollars, relative to the opposite sex, if it meant access to a wider pool of potential matches.
whatever more accurate numbers you want to substitute in there is fine, the point remains the same.
To be more explicit: you're paying extra to give more porn bots access to your inbox.
No idea how these businesses operate now. I'm sure there's still sliding scales of sliminess based on the quality of the club and its management.
(Sincere question, not snark)