He's Chinese. Facepalms and sarcasm go right over their heads. The Chinese are a very friendly and welcoming group of people but they have been isolated from the world so long they have no concept of any form of humor outside of their borders. Really.
You'd be surprised that despite what people think, they are a poorly educated lot who are book smart but have no practical usage whatsoever. They are a nice bunch of lads though to be fair, they just have no concept of the world outside of China. 我喜欢他们可是他们不明白我们的幽默.