I see your point Stix, but if you broaden it a little you'll see many ratings are heavily based on maths.
Perhaps your confusing ratings with handicapping a bit, although hadicapping can and often is used in ratings, or indeed used to arrive at a rating figure. There are many approaches possible. The ratings that I use as a guide to handicapping are 100% mathematically arrived at so maths is very important. They serve me as well as anyone else's. They are only a beginning point of selecting potential winners but nowhere near the final point. For this punter anyway.