@ch0si:
i'm not bashing this manga tho. [...] I like few shitty manga and i'm okay with that. Didn't change this manga into masterpiece instead of self insert manga with supernatural theme.
...Either your definition of bashing is significantly different from mine, or your words sound very different in your head than they do once put to paper.
Well, no matter.
Culturally, there's actually some interesting (if unanswerable) questions about why we might value "originality" differently—like, for entertainment media in particular, does originality even matter? (The difference in attitude has much larger impacts in other parts of our society, of course).
Conversely, while I'd agree that Japan shamelessly copies it's own stuff more than western cultures do, on the surface the average plot premise for a given manga is
way more out-there and weird than in western stuff; how are these two things reconcilable? But I digress...