I know I’m late to the party but I just found out and didn’t find a post regarding this
TL;DR: Steam now calculates review scores based on reviews made on your languages only (if enough). This is on by default, but can be reverted to go back to review scores based on all reviews (from people that purchased the game directly on Steam only)
They really don’t seem to understand that for most of the world we don’t care about China one way or the other. Much in the same way as I don’t really think about Argentina. It’s out there somewhere, but other than acknowledging its existence I don’t really care.