Because it doesn't make sense? This being a porn game doesn't mean characters must make non-sensical decisions. You(dev) clearly don't believe what you said yourself considering all of the effort you put into fleshing out your characters. Why would a young woman from a conservative small town, who is potentially still conflicted about her attraction to women, be totally okay with having  sex with a women who just admitted to being a nymphomaniac and trying to organize a small train run? Why would you force players to make this choice? Why would you offer a choice to not have sex with this woman, only to scoff incredulously at players who make this choice? I like this game and it has a lot of potential, but scenarios like these are insulting to the player's intelligence. It would be an improvement if you removed this false choice and actually allowed players to reject Jane's advances.