I doubt that the vast majority of students in any country are fit to critique a teacher on methodology, approach, etc., etc. but when you're talking about high school and university students who have spent most of their life in full time education then they generally know what they like (or don't as the case may be) when it comes to the classroom. Therefore, it is important for a teacher to seek their opinions on which aspects of the lesson they enjoyed, which they found the most useful and so on. You'll note that these are positive aspects as opposed to asking for negative ones. In my experience engaging such students in the learning process generally has positive results.

However, i can understand why in China many teachers are wary of student feedback because it seems that in most cases those in charge (FAOs, Doses, etc.) will use this and only this to judge a teachers ability. Perhaps (as many others here have suggested before) it is because those in charge do not have a good grip on teaching methodology themselves and therefore this is the only means of feedback available to them.

I don't think that any teacher who has even a little experience will not have had some negative feedback at some point during their teaching. It's how you assess the relevance of that feedback and then deal with it that is of importance for both the individual teacher and those in charge.