I am not sure if I understand. You have a country on Earth where the vast majority of people is one kind and happily co-exists with 56 minorities.
Can you point me to another country (the size does not even matter) where this happens like this?
> Soon after the establishment of the People's Republic of China, 39 ethnic groups were recognized by the first national census in 1954. This further increased to 54 by the second national census in 1964, with the Lhoba group added in 1965. The last change was the addition of the Jino people in 1979, bringing the number of recognized ethnic groups to the current 56. The following are the 56 ethnic groups (listed by population) officially recognized by the People's Republic of China.
How about Indonesia, South Africa, or Brazil? All are incredibly diverse and have pretty good inter-ethno/religious relations.
And I would not say that Tibetans nor natives from Xinjiang are happy with their current situation. The central govt has actively promoted the domination of Han people in these regions for more than 30 years. It has a real cultural impact.
Another thing from GP: 8% of 1.5 billion is a huge number of people!
As I understand, Japan and Korea are the most ethnically homogeneous countries in the world.