In the end, shows the author's limitation: Marika learns about Aya's (weird) past; Marika is still digesting the information, and says she is not in the mood for hentai stuff, as Rosalía would say; Aya and Marika end up discussing about their relationship; Aya is forceful (rape), Aya who explicitly said would never be forceful to Marika. The chapter was focused on getting empathy towards Aya. And here we all are talking about: rape. Rape or rapey, as you wish to say it. Overall, the set of actions felt off, to me that is bad writting.
On the intentions of the writing -- without getting into spoilers, the rape scene in this chapter is actually one of the major emotional climaxes of the story because it represents the first moment where Marika realizes her feelings for Aya.
Marika's reluctance to have sex is not because she is digesting Aya's background -- recall in the previous chapter, Marika caught Aya meeting Astarotte in front of Aya's house just after Aya called, for the first time, to cancel one of their meetings.
Hearing about Aya's middle school experiences makes Marika feel more sympathetic to/interested in Aya. However, at the same time, Marika had just confirmed that Aya lied to her, and is overwhelmed by Aya's confidence and sexual skills into thinking that Aya has tons of experience with girls and is just playing with her.
Marika's resistance to having sex with Aya in this chapter stems from JEALOUSY, and being unable to bring herself to believe Aya's sweet words professing her devotion to her. However, it's precisely this jealousy and insecurity which makes Marika respond powerfully when Aya finally makes her move, because, as Marika notes "In this moment, she really is looking only at me".
Aya, for her part, found herself unable to resist Marika precisely because she was perceiving Marika's insecurity and neediness. Yes, it was still rape. The scene nonetheless works as one of the highlights of the novel because it was for both Aya and Marika an amazing clash between their emotions and their rationality.
Between this and "There's no way I could have a lover!" I increasingly get the sense that Teren Mikami has kind of a sketchy idea of what makes a good romance. I would still say I prefer this one to the other, since even if that one lacked the more explicit scenes, just the overall relationship dynamic there felt uncomfortably predatory and manipulative. Here, there's at least the understanding that Marika is interested in Aya, and deep in denial about her own sexuality, that makes the relationship work for me. I really liked the first half of the chapter!
About Watanare ("There's no way I could have a lover!"), that series is actually an explicit, fully committed harem/polyamory series. Mai is the heroine of the first novel, whose role is to awaken Renako to the idea of loving women/lesbianism. She is by no means intended to be perceived as perfectly desirable or an idealized romantic partner. On the contrary, Mai's overconfidence and self-assuredness is often made the butt of the comedy in the series, as the second volume, featuring Satsuki as Renako's contract two-week girlfriend, is explicitly about Satsuki's quest to get revenge on Mai in response to Mai humiliating her at the end of the first volume (and Renako's attempts to get them to reconcile). Recall that part of the climax of Watanare's first arc involved Mai asking Satsuki to have sex with her, saying "You love me, don't you?", specifically because Mai was looking to have sex with someone she DIDN'T love to punish herself after Renako slapped Mai after Mai nearly raped her.
The most popular heroine in Watanare is in fact, by a ridiculous measure, Ajisai, to the point that it is almost pitiful how few people were rooting for Mai by comparison (although few actively dislike her after she helped push Ajisai to confess in volume 3). Nonetheless, the series resolved the love triangle between Mai, Ajisai, and Renako by making Renako commit explicitly to polyamory, so for as long as Mikami Teren can continue writing the series compellingly, there's no reason for conflict.