I think I'm coming from a POV that's different from most of you, but I'm absolutely not the type who thinks any creator has any responsibility to be "conscious" or "aware" of what they make - that there are any moral or ethical considerations that have to be taken when creating. A creator only has to create.
And so with that said, I don't really get the response to the last chapter. As someone else mentioned a few pages back, the series has a kind of telenovela feel with its sense of drama, and has since the beginning. The violence has often been treated with a kind of simultaneous over-the-top drama and shoulder-shrugging indifference. Shizuku's introduction is almost played for a laugh the way it catches you off guard and is so over the top, and Iori's sister's intro absolutely is. The series hasn't ever been consistent with the violence - be it the little smacks and boops between Iori and Minami, or the way Iori's sister and Shizuku throw each other around. Minami frequently showed up with bandages in the beginning - and no, this isn't justification for "oh, it's okay that she's beaten", but it's also not something that the series has played for drama outside of Minami's backstory and her time with Shizuku (and even then, their frequent fights in the past are played for laughs). I think it's obvious that readers are not supposed to take the event in ch. 22 as some sort of horrific point of no return for Iori - she wasn't malicious or sadistic about it, and it was obviously, I think, an emotional reaction in that previously mentioned telenovela way. Making so mich of it, with this humanities-department (and I say this as an English major) deep-reading cultural critique of domestic abuse is misguided and foolhardy when it's clear that this series uses violence as a means to an end or to set the stage for plot points rather than being "about" the violence as a critique or conversation instead.
Which isn't to say that I'm trying to invalidate anyone's feelings - react to the manga as you will, it's your right - but I don't believe that "calling the creator out" or judging the series based on your personal standards of right and wrong and responsible is worth it or defensible on a wider scale.