Hmm I don't really like the mc attitude. He cares too much what other think because he hanging with a beautiful girl. Let them be jealous!
On one hand, I get you. On the other hand, I'm tolerant of that particular thing, not only because of how judgmental the Far East is towards anything that sticks out, but also the way in which they act towards it. There's a reason this stuff keeps getting made. More and more people are relating to this in Japan and by social constitution, it is not designed to end.
She's not even any more popular than any other transfer student would be. It is expected that she would start making friends around now, so it wouldn't be weird for him to be one of them. There's no reason for them to hide their friendship.
Like, I don't actually have as much of a problem with the whole "hiding our relationship" trope as some people, but come on, there's absolutely no reason for it here. It feels like the author just included it for the sake of it. There's no justification.
The justification is less a direct plot inclusion (at this point, anyway), and more of a cultural subtext thing. MC is from the lower-end of the social strata, and by her not only being cute but also a transfer student, she gets to start off at the top and "pick a clique," something you can't do if you're already "settled."
MC already commented on his aversion to the spotlight she put on him, but consideration also plays a part in this:
Consideration is a significant and socially "desirable" quality in Japan, which is reflected and applied to how they write characters. MC acts selfishless here, but by not being "explicit" (another thing Japan is not particularly fond of; frankness/being real), the audience could insert justifications until they are vindicated or disproven.
Now, for my comment of this:
While I did say in the last chapter that I wasn't going to continue, I forgot that throwing it in my "Dropped" list, won't make me not get notifications... so I forgot what this even was, and my curiosity returned.
I did not expect a second childhood friend (lol), but blackmail? Nice. You know we love some coercion, right Japan? How else can you expect to get chicks, or at least learn how? (Please excuse the subtle racism, I don't know what came over me)
So, she's either a childhood yandere, or just a "quirky," socially clueless bimbo... who can socially blackmail? Yeah, I can see lonely men finding this hot and attractive. What could be more attractive than a women committed to controlling you, when despite the negatives, what you do get IS commitment, something you've likely never had?
I can sorta understand it... but not my type (Shin Hae-in from "My Bias Gets On The Last Train")
Why is the mc treating a close friend of his that he didn't meet for years like that???
All it can take is one confession going wrong to ruin relationships for a young'un, especially if you felt misled.