Responses
I like the way you think. Humans are complex. We always have a reason for the things we do, even if we, or others, don't don't fully recognize or comprehend that reason. It is still there somewhere.
This story was poorly executed by the mangaka. Though, considering the age of the story, it is possible that this was intentional. Until 2005 there were a lot of untouchable subjects in the genre. However, omitting the entire POV of the secondary main seems slipshod, at best, and lazy, at worst.
I don't know, should I hate the rapist? I mean yeah, he's a RAPIST but how should I know if he really is a terrible guy, his point of view or his side was not shown. Yes he raped Kei and that is an evil DEED but is the person itself evil? Well, this is just my point of view of the story. Maybe, It should be a bit longer to see if Kazuma's personality improved and to also have a clearer judgement of the characters in the story.