So Hikaru didn't like her because she was jealous and thought she must be trying to take her not-boyfriend. Yep that sounds about right. I knew a few girls like Harada back in college who ended up being "the girl" of the geek group and was just happy to find some people with a shared interest while the guys of the group thought "potential girlfriend" and it played out about the same. That they weren't exactly used to that kind of attention and didn't quite discourage it made it all the worse for everyone. It's exactly the type of thing you look back on and think "wtf was wrong with all of us" and the story really gets that right I feel.