apparently ratings are based on other shows you've watched and what Netflix would recommend to you
I thought this too, but I just searched it up, and it seems Netflix uses two systems (and is in the process of changing to one of them).
You have Stars, which are actual ratings. When you select a programme you can rate it up or down.
The stars are based on all ratings worldwide.
However, in place of stars, you may have "x% Match". This is how well matched to your tastes Netflix thinks each programme is, based upon which things you have previously watched, or you told Netflix you had watched when you signed up.
Netflix wants to change to this system ultimately, because the Star/Rating system doesn't reflect low-quality, yet popular/entertaining programmes.
It doesn't seem to take much watching of something though for Netflix to think you like it. So, if you watch even one episode, or just 10 minutes of one episode, of an Anime (including Pokemon for example), then it'll recommend other Anime for you to watch, and these will appear for you.