Because he's the hero Tokyo needs, but not the one it deserves right now, so we'll hunt him. Because he can take it, because he's not a hero. He's a silent guardian, a watchful protector, a JK Hentai.
@loksel
not really, but i can see where it is going following the usual "op harem protag" script writing conventions. the author could pull a satisfying ending or got the ax and deliver the shittiest one possible but either way the journey is not worth it.