No, I believe the whole rape thing is just another parody/trope kinda imo. It's like ... there are so many mangas that try to establish some form of trauma and revenge motivation for the mc and this is one common, easy way to do so (that i absolutely hate). At some point or another a love interst or some close gets raped/abducted/killed and it is just fucking annyoing at this point. Like its the only way for the mc to realize something to go through such a trauma to "grow". Fuck that, thats what the author is saying.I agree that the killing and rape was nothing more than the author not being able to think of a better motivation for the MC. But the characters not getting more than and introduction is not a bad thing since this was only chapter one! If this could continue then they would've added more to the other characters.
I also believe he knew he would get canceled after just one chapter, which is why he included so many references to other mangas in that one chapter. It is just a quick, easy, and quite elaborate big middle finger to everyone.