well, some people hate her because no matter how much Kishinuma saves or shows affection for her, she is mainly thinking of Satoshi. And also, in a bad ending of chapter 5, if you let yuka get captured, Ayumi goes insane and kills Naomi, ironicly killing herself as well. She also whines alot in the chapter, and gets possesed easily. That's the main reasons. Honestly, she's a pretty cool character to me.