People are too fragile to take this as 'joke'
I believe that some readers have become desensitized to what could be called, heavy topics. Especially when it's in the form of Manga or novels. After reading so many of these, especially from such a young age, I've learned to differentiate reality from fictional world.
As in, going into this knowing that it's a story doesn't really garner the same emotions in me compared to if this were to be something that I were to hear happen in reality. But I've noticed that this has been quite a controversial take when it comes to stories that feature things like this. Especially as of recently.
I think they immediately attached to the mc despite lacking his whole story. And view the downfall of the mc to be the 'bad story plot'. Basically most commenters and readers hated this are basically still young, didnt read anough manga, only stick to one genre (vanilla) and then come here first timers read dark manga and lashing out
Most people wouldn't find humor in this story as the Author said. But the absurdity of the whole thing is what I feel makes it very amusing. It's a very ridiculous story and that's what I find makes it funny in a way.