You can be raped and still chat normally with your rapist the day after,even hug them and laugh. (thats exactly what I did last time a woman raped me)
As for this author and mangas in general, you guys overthink way too much and give too much credit to the authors. It's just badly written and unrealistic, because this author's writing is usually bad and unrealistic. I still enjoy her work very much, but don't overanalyze. The author probably didn't think about all that. She just wrote whatever looked cool.