Except for 10th place all in the top10 also have glitched skillratings - not legitimate. 11th place also an alt of a routined player (almost same name and mod, quite obvious) taking advantage of the system by making a quick 32 winstreak and not playing with it anymore... A few more high up who haven't played enough for an accurate rating... But yeah just look away from the top9.
Other than that it seems to be similar to chess ratings. So your rating goes up/down relatively to how high the rating of the people you're playing against are. You can't drop in rating if you win the race though.