Frankly, I don’t buy the 3 deep 4 u explanation about it being a subversion of vampire tropes that was supposed to teach the audience some kind of lesson.
Yutaka himself says that Genjins feel differently about it, so it's absolutely a subversion of the trope, since it's not sexual in nature for them. It sounds pretty literal as an explanation to me. It's not about the "lesson" that we have prejudices blah blah, it's about the manga's world building, where Genjins are few and humans have prejudices against them.
This entire post feels like it put infinity more thought into this than the author did. [...] And, yes, the primary point of the scene was to showcase jealousy, which is why Senga literally said that. Most manga are not that deep. They tend to be pretty literal with what they're trying to convey.
Also, this was literally just what I gathered from the chapter when I first read it. I didn't even think deeply about it, it was just my genuine reading of the chapter's themes. The whole "Genjins function differently and have different needs" thing has been thematically consistent ever since the first chapter. Believe it or not, the author has actually put time to showcase differences between humans and Genjins. The main character himself thinks about this sort of stuff all the time, which is why he even goes "this is normal for them, BUT if it were humans..." implying that the implications don't really apply to Genjins. It IS a theme of the chapter and it's laid out just as clearly as the whole jealousy thing. Of course Yutaka being jealous was part of the chapter's point, but it wasn't the
sole point is what I'm saying. It's partially about Yutaka feeling uncomfortable by his human values and partially Genjins treating social norms differently, as it's been showcased multiple times in the past, like Tsumiki sniffing Yutaka's hair as a greeting and friendship-token, which is perceived differently by him.
It also doesn’t address the core issue of why Tsumiki would even agree. She’s established as not liking Senga. Senga is established as being more than capable of finding plenty of sources of blood, so he wasn't in danger, just mildly inconvenienced as a result of the behavior Tsumiki critisized in the first place. Your only explanation for this is the extremely vague “Genjin are just, you know, different from humans and they do stuff like this for reasons.” How convenient one those things they "just do" involves what most readers would view as a supernatural kiss.
Again, Tsumiki just found it logical that he should drink some blood since he was hungry. It's pretty okay to me, it just feels like she was providing him with food in good faith. Her not liking him much is pretty much irrelevant, because they understand each other's struggles. He needs blood and he is hungry. I bet the whole reason he has so many girls in his contacts is because it's hard for him to actually convince them to drink their blood non-transactionally lmao. For Tsumiki, it's genuinely a non-issue. It means nothing to her. Thematically, it's coupled with the jealousy issue. They aren't mutually exclusive. They're tied together to promote the ideas of jealousy through his misconceptions as a human. Voila, a more grounded, more believable conflict.
And yeah, Genjins have different needs that humans haven't adapted to. Drinking blood is a vampire's need and they will drink it. It's not vague, they don't "do stuff for reasons". They exist in a society where they aren't the majority and they function in different ways that humans perceive falsely. The readers perceiving it as a supernatural kiss is definitely the point, but it's still just inside their mind, just like the MC's. It's pretty hard for me to view it as NTR or something actually lewd. After the meal, neither Tsumiki nor the vampire feel differently about each other. I can't really read it as if something substantial actually happened, since it's just the MC being a human and being jealous, which is, again, still part of the reason this chapter exists. If the lewd page was entirely removed and the MC just split them, nobody would mind it, because ultimately there really were no sexual implications. It's just the image itself that bothers people for reasons that I can't really agree with.
The one thing I could agree with is that maybe the chapter's message could have been the same without the depiction of an erotic bite, but I think the theme is much more effective and striking if it's included. I also get feeling like your expectations were betrayed in a sense (even though I don't feel that way), but I don't think ultimately the core concept changes or that the story will lose its fluffiness in the future.
Most manga are not that deep. They tend to be pretty literal with what they're trying to convey.
The one thing that I really, really disagree with in your comment is this though. It almost feels like you're underestimating creators' intentions. I believe that most manga out there, regardless of whether they do it well or not, actually put some thought to what they want to present. This specific manga, too, has definitely put some effort into world building and the dichotomy between humans and Genjins. There is absolutely no reason for me to believe that there is zero subtext to it all. It's very clear that the chapter's conveying the idea about Genjins not having the same social cues as humans and, just like you said, it is being very literal with it, with the MC literally saying that same thing right before his fantasy lol.
And given the massive negative reaction by 95% of the readers to this chapter, I'd say doing so was detreminemtal in the long run. By all means go on thinking you and the few people defending this chapter are a special secret club and no one else truly understand's the author's vision, but genrally speaking, when the reaction is this bad, that's a pretty big indicator the author made a fundmental mistake in what they were trying to convey or how it was executed.
Also lmao at believing I'm some sort of elitist or trying to belittle me like that. I hate elitism more than anything. It's not just a few people, I've seen many comments on reddit holding the same thought that I did. When people genuinely thought that the erotic bite was real, then yeah, I think there is grounds to say that they literally didn't understand the chapter or read it too quickly. When the creator themself had to come out on twitter and confirm that it was indeed a delusion, something's gone wrong already. That's all I was pointing out. And at this point, the only mistake I could regard the author with is that the scene didn't have to actually portray the erotic bite. People thinking it wasn't a delusion is totally on them, as it's explicitly explained and shown before and after that there was nothing sexual about it. Was the author supposed to have a little note on top saying "this is Yutaka's fantasy"? I don't like it when ideas are literally explained to you at large. The subtext and signs are there and they are clear enough in the execution. But more than anything, I implore you to rethink the whole "not deep" argument. I also don't believe the manga is particularly "deep" but there is absolutely effort put into creating a different class of people. If you reread the chapters, you will see that the world building has been subtle but it's absolutely there.
I, for one, think that this massive reaction is misplaced, not necessarily wrong. If people didn't like the sheer visual depiction of the scene in an otherwise wholesome manga, that's what they should be complaining about, not that it's "NTR" or that it was just a sick fetish or whatever.
TLDR; I personally don't mind it at all, but I could see why it would be bothersome to others. Everything else checks out though, both thematically and tonally, and my "overthinking" is also very much intentional on the author's part, to the point it's literally explicitly mentioned in the chapter itself.