Nothing happens by accident with Official China. This was not one rogue bumpkin at the airport and then another at the guest house. This was deliberate.

Official China is exacting about diplomatic protocol. Zhou Enlai was still bitching in 1972 about John Foster Dulles' refusal to shake his hand in 1954. Form is elevated to the equal of substance. Nothing is surface-level. Chinese employ symbolism to an extraordinary degree.  They know of Jim Crow segregation laws in the U.S.

Chinese are the most race-conscious and the most racist people on earth. They constitute the Middle Kingdom of the universe. One is always Chinese; race trumps all. You emigrate, you're still Chinese. Your grandparents emigrated, you're still Chinese. Gary Locke's grandparents emigrated from China to the U.S. He was still Chinese to Official China when he was U.S. ambassador. It's exactly like "the Mexican judge," to Donald Trump. Judge Gonzalo Curiel's grandparents emigrated from Mexico to the United States. Curiel, like Locke, was born and raised in the U.S. Still Mexican to Trump. Locke was still Chinese to Official China.