Really? Tell that to all the polyamourous people out there who find it impossible to maintain monogamous relationships. And bigotry against consanguineous relationships under a story about another controversial and taboo relationship? Wow. Besides you missed the entire freaking point. People hate the ending because the uke is an ass (I also think Ayumi is an ass but that wasn't the point the others were trying to make, either). He doesn't care one whit about his brother and Koshiro gets pushed to the sidelines while having to take all the blame for his BROTHER'S actions on HIS shoulders. Horrible ending. And crap couple.
actually..I like the ending. it is impossible to maintain relationship as threesome. to add with that, atsuchi is his younger which is incest and big no no to me. I like Ayumi end up with Takashi ^^