I also didn't expect that sudden rape scene, but I believe the people, that are outraging about it, might be a bit confused. They have to ask themselves, if the real question here is, "Does the evil cat girl deserve to be raped or not?", or, "Is it okay to portray rape as a form of punishment in general?", which is what the author just did. He used it to punish that character.
I didn't reread the scenes, but other commenters already pointed out, that judging by her prior behavior, she has a shitty (Yes, you may say downright evil) personality. When most people say, ""Yepp. She deserved it.", do they really mean she deserves right that form of "punishment" on a moral basis? Or isn't it more like, they stopped to care about the well being of another person, that does harm to others, and are fine with whatever stops her in her tracks, satisfying some low key, lingering thirst of instinctual justice?
So yeah, I'm also not okay with this sudden change in edginess of the manga. I'm okay with revenge mangas and I like many of them. But I don't believe it's the right thing to insert this slide of darkness without prior warning, as it upsets a good portion of its reader basis. It lacked impact and was unnecessarily cruel in a scenario, that didn't ask for it. You'd never expect it going into that direction. There are other mangas, that focus on being immoral, by offering cruel punishments as instruments of justice. Therefore you are dumbfounded by it and if you can't stomach it, of course you complain. They are upset about it and rightfully so. They read a wholesome story about a person, to whom good things happen and who deserves it, and suddenly something happens, that ruins this story for them (for a bit at least). I wouldn't be a happy bunny either.
