Responses

Because she was blocking the hero (her "fiance") and the heroine (the crown princess) from being together. She's also done a lot of stuff to keep other girls away from the hero, due to that, no one believed her when she said she didn't do it.
So although she was a victim to another's plan, she was still a villain in the story, probly had more than 1 villain lol who knows
How is she labeled a villain when even in the original story, she didn't intend to poison the princess?!