it is because of the incest patch, Sumo did not want to make the sister a love interest for the actual version of the game that would affect the censored version.
in the incest version the reasoning is solid for OUR realities sake even though she was really REALLY interested in incest, and pretty much forced everything just to almost confess romantic feelings the following day after their romp, just to go "nope, cause it's incest, even though i blew you, gave you a tit job, masturbated together, fucked your brains out, let you cum inside all night long and almost confessed my deppest feelings for you, nope just nope because people will judge." even though pretty much everyone else in the game literally seemed to not give two flying fucks if they did, if anything they all gave off the feeling of being supportive for it if they found out. Also not to mention it is only at that part where she is spewing the bullshit, does she only at the moment care what anyone else thinks.
for the non incest version i am sure it is some nonsensical bs excuse just to make it not happen, aka lazy writing. Honestly if sumo did not want people to want having Nikki as a LI, he really should not have bothered with writing her at all and should have just made the MC the football guys roommate who could help turn him into a chad. The story would have pretty much went the same but flowed better without all the bs excuse making.
Thats basically what i wrote a few weeks/months ago. Having the sister there doing all kinds of stuff then reaching a point that hints to feelings and then cutting everything off made the whole point of the character being there absolutely pointless.
You can literally change the sister to a male and cut out the sexual content and you wouldn't notice a difference here. IT IS NOT LAZY writing however its just not wanting to go there with his writing despite the fact he already went there.
I write for a long time now for a living and can say alot of people even pro's like myself walk into that trap where you in the flow of writing go down a road you never intended but it feels right in the context of the character development.
However if you don't wanna go there the lector will show you how flawed your logic is and call you out on it and if you want your book then published you either rewrite that so no indication happens or you split the character story apart so that the reader only finds implications that can be seen in multiple ways and its up to the readers to decide what to make of them even tough it ends up a completely other way you maybe thought as reader.
To give some prime examples where you might thought there is a romance going on only to find out there wasn't one in the first place or the fact that the romantic feelings are part of what only one side wants while the other one has already went on or yet another twist you as audience/reader would not have seen coming.
Game of Thrones "Tyrion and Shae"
Cruel Intentions "Not gonna spoiler anything that was a masterpiece"
Forest Gump "And no i don't believe for a second Jenny loved anyone but herself"
The Fountain "Starring Hugh Jackman and Rachel Weisz where the distinction between reality and imagination is almost impossible"
Tristan and Isolde. "Not gonna spoiler anything here either"
Casablanca "Masterpiece"
Gone with the wind. "Masterpiece"
I disagree with the dev entirely to not make the sister a LI but at the end of the day its his game and his decision also the decision of the paying patreons what they want or demand. So all we can do is mention it and suggesting a different outcome but thats about it.
It doesn't bother me either way as i lost interest in this project the moment everyone including the dev stating that the sister will never be a Love Interest despite the fact she already was going by the events unfolding in the story. Thats like stating Bruce Wayne is not Batman when we on screen see exactly that he is. Kinda pointless to discuss the obvious then ^^
