Review of Koi Kaze

This show literally was just one scene away from being great. One scene completely ruins it and changes what could have been a pure and responsible relationship into an unforgivable mistake. Love can have many forms and meanings for different people, so maybe many will disagree with me. I think even between siblings, it is completely ok to say openly that you love each other, to hug and be physically close. It is not common, but it is not necessarily bad. Physical touch can be comforting and calming. It doesn't need to cross into lust or pleasure. There may even be cases where it's ok ifit eventually does, though I know I'm getting into muddier waters here, so I'll stop. It is irrelevant to this show anyway, as a clueless 15-yo girl saying she loves her big brother certainly is not such a case. There clearly can not be any lust from her side. Thus any from the brother should have been kept suppressed.
Yet for some reason the show's authors seem to consider saying the word "love", a hug, and sex equal. Once you break one, you got no choice but go for the other too? There is no middle ground? There was not even a hint of a possibility or an attempt to treat them as separate, or to only suppress the worst of them. And I've seen the same in many other shows about incest. Is that a Japanese thing? I don't get it, but it completely ruined the show.