The story goes that the mangaka knew he was getting the axe, so he wrote that arc to spite his publisher.
I don't like the content of said arc, but I can respect the man for going out on his own terms. Spite is a very spicy dish... When served correctly, it burns soo good.
@MrMcNasty
I didn't even read those chapters, the moment i read the TL warning i knew shit was going down fast, the ending was pretty decent ignoring those chapters.