Chinese people ARE ASIAN.
Why would they be racist against their own race?(unless they have serious inferiority complexes)
The reasons that they don't want to hire Asian looking people is that:

A/ Students will complain about it
B/ Parents will complain about it
C/ Teaching English is big business these days and it pays to have a "white head" in the class room
D/ People like Black Serpent will get jobs

I am not justifying these reasons(with the exception of D) they are just the facts of the matter. If you are a qualified English teacher or a native speaker I really do feel for you, but otherwise, learn to use the language correctly before you even consider teaching it.
Oh yeah, Turnoi is a tool.