Short Astronauts
They don't need to design for big. With 1.2 billion candidates, they can pick small first, then go for smart, quick reflexes, steady nerves, and the Right Stuff.
Name your discipline, and I'll find you ten world experts in China...
OTOH, Size in China is partly a nutritional issue - in the modern era of McDonalds and "little mandarins" (single kids who are spoiled rotten, and suspiciously over-represented by males), they are growing larger, but China is still the only place I've been where I could see over the crowd from my glorious vantage point of 5 1/2 feet on a good day.