Glad I wasn't the only one who found this annoying. Guy holds onto some shit that happened a million years ago so he's angry and only knows how to yell at and punch the other guy when they reunite... and it turns out to be love? F dat shit.
its supposed to be a "boy teases the one he loves scenario"
Kanaga was confused about his feelings and jealous that Miyama was popular and did stuff to get his attention but didn't realize that was why he was doing that.
Its not well explained but that what Miyama meant by "Hate is close to Love" Kanaga's hate was just his anger at being affected by someone and being unable to understand why so he became angrier.
Basically "I'm 8 and having weird feelings, wtf. It must be your fault. I hate you." Kanaga never grew out of that stage apparently.
That last story was the best, so intense. I'd really like to read more about it. Sigh.