To be fair, in this case it's probably at least partially coming out of people considering animation to not be "true cinéma" (pronounce "cinema" in your mind in the most pretentious manner possible). I swear, every time there's a /r/fantasy thread about an adaptation of something there's somehow always a bunch of people crawling out of the woodworks going ":wojak-nooo: nooo you can't adapt this totally mature and highly original work as an animated series, that's children's entertainment!"