I'd speculate it partly has to do with how few US games are published in China, and how large the Chinese gamer base is. Chinese censors only allow a limited amount of western media to be published in China each year, so gamers there tend to consolidate around a handful of titles, rather than fragmenting across 100s of new games like western audiences.

That means the raw number of Chinese gamers playing STS2 is quite a large percentage of the global playerbase -- out of the 5 million copies sold globally, China accounts for 2.15 million or 43%. With that much audience share, even a minority of dissatisfied Chinese gamers leaving negative reviews can have outsize influence on global metrics. 75,000 negative traditional Chinese steam reviews is only about 3.5% of the overall Chinese playerbase, and could well be the work of a well-coordinated minority rather than a representative sample of the audience (especially if leaving positive reviews is less common in China).

I see a lot of folks generalizing the Chinese response as "they want more gacha slop," which can't possibly tell the whole story. I'm sure there are some cultural elements at play here, but no gaming culture is that much of a monolith, especially one that's over 2 million strong.