Ya, I didn't cover them but there's certainly exceptions. Kids shows is a great example of a genre targeting a demographic which is likely under represented by the voting community - adults. Imdb is best viewed through the filter of "what do adults want to watch or think is good".
I remember watching duck dynasty, great kids show and I loved it, but I doubt it holds up for adults. Batman beyond on the other hand won an Emmy and still falls into the "kids show" genre but is very watchable for adults who can appreciate animated content.
So to answer your question, Netflix needs both as they represent very different audiences.
A few other exceptions that I didn't mention are comedies and horror. Ratings for these skew lower than average as they aren't meant to compete with Shawshank for greatest of all time, simply to entertain or scare. As such neither of these genres tend to attract serious directing, writing and acting talent and in turn, audiences tend to view them more as "fun" than serious.
You or I might love to watch pineapple express, hilarious comedy, but still vote it as a 6.9 because it doesn't hold a candle to Shawshank.