I think its because with these newer villainess/side character stories have developed a trope for having the original angelic heroine be a two faced b*$ch. Peoples expectations are subconsciously set after reading a few stories that follow this trope.
So far I get the impression that the sister actually is good and may have her own issues. Everyone loves her but does she really feel comfortable with it? A few scenes she looked a bit upset. Maybe things aren't quite as rosy for her as first impressions suggest.
I thought she was evil at first cause I thought she was taking advantage of situations where she could make her sister look bad. Like cmon when her sister apologized the girl fr ran away crying and also with the scene of giving her sister a gift, girls around be making fun of her appearence and then when she confronted the bully it be making it like she is the good one and really does "love" her sister. But yeah ig for now I've accepted she really does like her sister and I do like the vibe they both have now :).
Why do people think her little sister is evil? Not even in her past life did she ever show that she was mean and was always kind to her big sister even until she was banished not to mention she defended her when she thought she wasn't there @-@ she hasn't done anything that would even be considered evil towards anybody past and present you guys just think she's mean or might be because... She's too nice? @_@