I think you are wrong to say that some foreign teachers are tarnishing the image of ESL system in China.At this point i think this can only stop when our students,parents and school leaders will keep away racism and move forward to merit.For,i don't think i can really teach Chinese in another country when i'm not educated.
There are many good teachers out there and forget about color.We are here to give good education to your children
and not a show.WE SHOULD CARE.