There may be a corellation between ethnic background and what they play but not the cause of what they play.
One thing to consider is location. If a person learns music in China, that person would almost certainly be learning things that were taught by someone who learned from someone who learned from someone from the West. And the repetory that the Western person taught would have initiated a long process in which the repetory would be passed down from his students. Any new repetory that the students have not heard of before would not be passed down.
Another factor is language. If all of piano music texts were written in Western languages, then only a few Chinese persons who have learned those languages would be able to read about those composers that were not initialy introduced to them. Not knowing about the vast composers would limit the choices that the pianists would seek. So the repetory that they choose would still be of the composers that have already been introduced.
Another factor is time. Composers of the more modern era, Rachmaninov, Liszt, Busoni, Satie, Debussy, et al, would not have been introduced to the students of the Western teacher as he has not heard of them before. You cannot show someone something if that something does not yet exist. Now with the increase of the flow of information, unknown composers or composers not very popular are able to be shared among pianists. One example is Charles-Valentin Alkan's compositions. He was very obscure until recently.
There are three factors that limit the repetory that a person knows about and performs: location, language, and time. These factors dictate what a student would learn and add to his repetory. But there is another factor that I will expound on latter that affects the choice a person makes when choosing pieces.
What would a person in China who is learning the piano play? Most definitely the works of the big three: Mozart, Hayden, and Beethoven. Other popular composers are Schubert and Chopin.
Schubert and Chopin have a different style from the Big Three. They tend to incorporate beautiful melodies throughout much of their works. They are also less complex than the Classical composers in this manner as the melody is almost always dominant and can easily be focussed on. This characteristic trait is also found extensively in Chinese music: the melody is dominant with smoothe lines. This is one reason many Chinese pianists prefer to play Chopin and Schubert: their music is the most compatible with their ethnic music. It would be more natural to be drawn to music that is most similar to ones own. It's cultural.
However, the musical scales in Chinese culture is more fine tuned than in Western music. Western music, compared to Asian music, is primitive with large leaps from pitch to pitch whereas Asian musical intervals are much finer allowing more delicant pitch changes. From a person who has listened to Asian music most of their life, listening to Western music sounds "noisy". "Noisy" is what one of my music professor's mother says of the music he listens to who is from China. It is in fact noisy should you take up listening to it exclusively for a week and then going back to listen to Western music; the contrast is stark.
Now this "noisiness" of Western music from an Asian perspective may limit the repetory that one chooses. Children of Asian descent often have troubles distinguishing where the music is in Western music. The reason is this: Western music seems like noise more than music. This could be a reason why some children just don't know what they are hearing and just play the piano by way of fingers, just pressing the right keys are the right time.
Backtracking to Chopin's music: it may be true that many Asians prefer Chopin's music than to any other composers' music and may be because of Chopin's style of using the chromatic scale to bridge the 'gap' between pitch changes. Since the chromatic scale is much finer than the 24 Western scales, the chromatic scale sounds more "whole" without the gaps in the regular scales.
So now there are four reasons, the cultural one being the most significant in my opinion as cultural differences are usually the most difficult to overcome.
Topic: Race and Differences in Playing