lack of comprehension skills, obviously. all the works of this mangaka is phenomenal, yet they average on 8.5 ratings, while there's many examples on this website of some of the worst mangas raking max ratings lol
Cuz it's not popular mangaka
about the no chapter ones... the high rating might be the default, which then gets lowered or stays the same as ppl start rating it (or at least that's what i think) or maybe some ppl read it already on some other platform so they rated it here once the manga page was created.
Some empty series (no chapters) have a high rating and some, like this is rated low....why?!