the rape scene

Honestly I don't think so.
The Guy who raped him has some sense of 'pride' and he couldn't handle the fact the the protagonist refused him. So he gets back on him. This happends in real life too, why do you think people get raped while going out? That is because in some cases the victim did something to damage their 'pride' and sometimes you get the reaction in an instant or it takes time for example by stalking.
(Ofcourse there are more situations/reasons/examples)

And for the uke in this case. He shuts his feelings down because if you read the story he doesn't want to depend on anyone. He is glad that he has a roof over his head.
Of course he doesn't want to get raped but I think that he thinks that there are worse things than that.

These are my thoughts on your opinion :)
Please don't shoot me ヾ(❀╹◡╹)ﾉ~

(●￣(ｴ)￣●)

I also agree that the rape seen was unneeded. at first I was also triggered when sazawa said there's nothing they can do about it but then most of the time rape victims are the one who doesn't want to have anything to do with what happened. as much as possible they just want to put it behind but that's not how easy it is. they do want to but the traumatic experience is really just the worst... but that's how offenders get away from their crime.

as for the rape, Fumichi didn't want to dwell with it... to me it seemed like unlike the other victims it didn't really affect his psyche as much as what we know of. there are more worse problem for him as @thelegendofloki said and being taken advantage of is not really one of his worst.

it may seemed like it wasn't really a big deal... well for Fumichi. it's like whatever happens happen for him.

anyway rape scene is unneeded. hopefully mangaka used different a different scenario to show Fuchimi's personality....

or... that's how mangaka sees the easiest way to do so.

I blabbered enough... no offense intended