Teenage boys fantasize about being powerful and being able to fuck any/every/all woman they want(singly and simultaneously), including those forbidden to them. Male players of all ages remember those days in their lives. So there's a certain appeal to the embodiment of that fantasy in game form. And why you don't have as many Chad Hardcock, intrepid adventurer games, or games where the MC is some kind of awesome superstud from the jump. Those are wish fulfillment too, but perhaps too remote from the player base's life experiences for them to identify as/with the main character.
Just a theory.