p. 19: Hikaru: "I don't know why I'm getting so irritated about this."
Um, maybe it's because your uncle is an idiot?
He somehow feels that there is no way anyone younger than he is could be interested in him. NOT!
He denies the validity of Hotaruko's feelings, because she is so much younger than he is.
Mind, given that he thinks of her as daughter, his not reciprocating is OK, but denying that she feels this way isn't.
He feels that since the TV lady is a dozen years younger, there's no way she could be interested in him.
This, in spite of just how blatant she is being. Subtle, she is not.
Which says she's got his number; subtlety will get her nowhere.
Uncle-san, wake up and smell the coffee!
Hikaru, you have every reason to be irritated as all get out.
Now, to continue reading the chapter.
Done reading...
Hikaru, I salute you!
You succeeded in expressing your feelings for Hotaruko to her, such that there is no ambiguity concerning them.
Knowing that she wasn't interested in you that way, but knowing that if you didn't confess, she wouldn't understand why you were so concerned about her, that's a very bad position to be in.
Yes, things will be exceedingly awkward now, but if you hadn't, she would have completely turned away from you as being one who interfered with her life for no reason she could understand.
This, she should be able to understand.
I'm not saying she'll be happy about it, far from that, but at least it's comprehensible to her.