Chinese players don’t have access to most of the established feedback channels like the official discord server and social media accounts so their only option to reliably get the devs‘ attention is through Steam reviews.

But there is definitely a cultural difference as well.

I think these two things might be related. When all you've got is a hammer, everything is going to look like a nail. The devs can add all the in-game alternative contact methods they want, if Chinese players are only familiar with using the hammer and that is the only option available to them, that's what they're going to use. They're not going to suddenly try something ad-hoc like finding a feedback button buried somewhere in the game, when the nail is standing tall right there, just begging to be hit with their hammer. They've been trained to use the hammer, they're going to use it first, immediately, and liberally, and the idea of using or even considering an alternative will probably never occur to most of them.