Penelope isn't the villainess first life, she had another before where she was an important and liked mage, but due to the actions of a cult, a powerful supernatural being came out that she tried to stop before dying, but as she died, the being cursed her soul, basically, any future life of hers will have it so that people naturally hate her guts and want to abuse or kill her, even if she doesn't do anything bad, people will just mistrust her, Penelope spent her entire life not knowing about her curse and just had people constantly attack her and mistreat her until she snapped and decided to stay in the mansion because, constant abuse from everyone or not, it was still better and safer than going back to being a commoner.
Particularly since Penelope was heavily misanthropic and cynical because, well, pratically everyone she met would hurt her or screw her over, and it's implied she purposefully attacks or acts like a brat to everyone because she lost any faith that people could ever actually like her, the main character taking over her body and soul does seem to diminish the effects of the curse over time though, with some people actually feeling sorry or recognizing they went too far, the maid we see here giving her spoiled food and smirking?
She goes from hating Penelopes's guts to sincerely begging for forgiveness and deciding to help her however she can to make up for what she did to her, and starts to become speechless and wonders what the hell she was thinking giving her that kind of food and abusing her, mostly because the curse stopped working on her and she actually just feels shame and regret at her actions, basically, because of the curse, it wouldn't matter if Penelope was a living saint or the worst person ever, pratically everyone would hate her no matter what.