
I don't think the author was aiming for this. They were probably acknowledging the cliche of the overused backstory for characters like ML here, it's the same rinse and repeat backstory. (I feel a bit off calling it a cliche but oh well ig)
Yes the author may have unintentionally made this come across as them joking around with such a sensitive topic, but I think (and hope) they just didn't fully think it through?
Keep in mind I know nothing about the author, just wanted to provide a other potential side of the story.

I did not feel that this was troll (by the author) on overused tropes at all.
Whatever their intention was, I still feel it's not something to joke about. Under any circumstances.
It's not just this author, there are many who use rape, child abuse and all sorts of sensitive topics as comedy. And there are many more who show child rape when it is not really necessary to the story at all.
I am someone who looks at things from multiple perspectives, but these are not the topics I need or want to be liberal about.
This disgusting writing.. Why bring up child sexual assault and Pedophilia in the passing? And more over make it all a joke. What is wrong with these authors downplaying such sensitive topics. Disgusting.