@MonsieurQuack If all we saw was the image where Iori grabs Minami's shirt I might agree that it was just poor use of artistic exaggeration. And I don't think the author intended to depict abuse. But you need to look at the context.
This chapter is framed around Minami coming to work with bandages and her co-workers being worried she's been abused. And then at the end of the story Minami is the only one apologizing. In that context the slapping doesn't feel like exaggeration. It feels like abuse that Minami doesn't recognize is such. Lines like "It was my fault" in response to her co-worker's concern add to this.
It's also important to consider the context of the overall manga. Minami is a character who has survived intense violence in her past. Her relationship with Iori is constantly being framed as her escape from that. This is not a good couple to exaggerate physical violence with. It makes it seem like Minami escaped one abusive relationship just to end up in another.
Again I don't think the author intended for this to be abuse. But I also think the criticism this chapter received is justified.