The problem isn't that in my opinion. It's really hard to argue anything these days because people just throw a label at you and disregard a opinion they don't agree with.
Right now, my problem with the story is that the tone shift was horridly handled, I don't even know why he decided to go for the lowest hanging bag of traumas he could get. Yami's character turned out to be a sad girl for reasons that are barely relatable to anyone, her issues are all super serious stuff that's present in many other works when an author want to garner some quick pity for their characters, multiple of those cheap hooks.
Right now, I feel this is just vulgar, blunt and unintentionally funny. It doesn't have the nuance and depth required to generate a complex mix of feelings that could make this story stand above others and you connect to the characters beyond coming to some discussion forums to fan the flames for a bit. the only reason people are even bothering reading this in the first place is because they were baited by either the beginning of the story or the shitstorm that followed the twist. If the story start from this segment of the story it would be straight up trash from the beginning.
One could say he succeeded in marketing by making people react to this? Does this mean the series is good? The ratings plummeted everywhere, the story used to reach 250+ likes in their official site, now it cannot even reach 200 anymore. It generated buzz but not in a good way.
I mentioned Honna Wakou in my previous comment, and I think that's a pretty valid comparison because right now this feels like reading Nozoki Ana but in a situation where the author is asking us to have sympathy for Kotobiki out of all characters.
Sex doesn't make a story mature or good by default. Molestation, abuse, prostitution and whatever else was in Yami's past also don't. Stalling the story for this cheap flashback isn't doing it any favors.
Couldn't have said it better myself really cause this whole time I'm just thinking, at an author's standpoint, "What is the point in all of this? What is the meaning they are trying to have us derive from this?" Especially since it wasn't hinted at all before all of this occurred and y'know, like, what even is the purpose? I just don't get it, why write it if there isn't a purpose to it? It's so out of the blue that it's hard to sympathize with this character who is essentially a stranger to me. I've seen comments talking about how "it's interesting to explore this" or something on the same lines but like, why? What is the draw to a plot point like this when there is no meaning or purpose to be derived other than a random right hook you get after rounding a corner in the street? Sometimes being unique isn't always a good thing. It's just pointless drama essentially, I see no point in it.
Mind you too, we're talking about a story. If the purpose of this story is to go, "Well, look, nothing is ideal and sometimes reality is like this" or whatever and the main character somehow doesn't end up with the dude, it once again begs the question, "Was there a reason to make this a story?" to begin with since that's not a meaning to derive from or a real purpose, it's just cynical and bothersome reality.
At the end of the day, I'm also thinking, "what sort of progression will this lead to for the FL?" What sort of character arc are we even supposed to go to from here on? What about this situation will progress her character in anyway? She'll just go, "Oh my god, I missed my chance" be sad and then get over it or? These are the questions I have really.
Note: I should clarify by the way. I DO NOT hate these characters. None of them, I do not fault them for any decisions made. I think this is completely the fault of the author cause I legit do not give a single shit about this girl who was essentially relegated as a side character before this who had zero interactions with the ML before this moment, I quite literally do not give a fuck about her. I feel nothing, literally nothing. Not even after hearing her pitiful backstory that was suddenly trauma dumped onto me. Sorry for the harsh take but, yeah, I just do not care.