This is just art. Anyone reading this series probably came to see the dumpster fire, Ueno getting dominated was how it started, ppl who wanted something else probably gave up quickly. Then the author proceeds to develop the characters and even make us feel bad about not rooting for this guy who is trying to move forward, and when it seems like Ueno is extremely close to completely evolving from his dark past, the author throws this curveball at us, and it is great. The author gave us what we wanted after making us root for the contrary