Tracy Jordan's entire character is not being a Black stereotype, and making fun of the discrepancy between his character and the stereotype. Jian Yang is an Asian stereotype.
The character of Jian Yang is a very specific subset of Chinese nationals, namely those who come to work in a very specific industry in a very small part of Northern California.
That's like being upset about a show with a character poking fun at Americans who teach English in South Korea. (Which, I'm guessing, could provide some pretty good material.)
