Because you are using the incest mod.
This isn't an incest game so the dev has nothing to do with the mod, you'll need to speak to the person who made it.
Why would anyone play this as an incest game!?
I like a "good" incest game as much as the next guy, but this game was clearly never meant to be in that genre??
I mean the main plot is your dad "fucking" you in the ass as much as possible, leaving you homeless with nowhere to go.
It's part of the main plot of the story!?
In a lot of games, removing the incest plot, makes the game very poor and sloppy, having landlady's and room mates that for some or other un-explained reason feel it's not appropriate to have sex with them. I mean WTF?
I mean in this game there is never a hint of this. The girls are clearly very flattered by your attention from the start.