The outrage on this thread is funnier than the actual manga.
LOL - you want a dumpster fire - you're missing Konbini Goutou. That makes this manga look like kindergarten scribbling.
The MC isn't any less likeable because he's no longer a NEET Virgin. And Senpai isn't a hussy for taking what she wants.
Readers complain about hundreds of chapters of blue-balling like Kanojo Okari yet someone finally DELIVERS THE GOODS inside of fifty chapters (and in a understated artsy - dare I say - tasteful way) and it's worse than Solomon breaking out the longsword next to the bassinet?
Seriously people.
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.