Man, some people really know how to get offended by a porn game, of all the things to get your panties in a twist about you choose a game about incest. That's just hilarious.
If you don't like the game, or the route that it's going down, that's fine. You can do this thing called 'don't play it anymore', there's no reason to debase the game for imaginary reasons.
Last time I checked, no one is a Clairvoyant, so I somewhat doubt peoples ability to know how the game will progress. If the game rustles your jimmies so much that you feel the need to lash out about it, then you obviously care somewhat about it. So maybe just let the dev play it out, and see what happens in the future, instead of considering it super-mega-ultra ruined because the game has a touch of femdom in it.