[rabble]

eslHQ
I am afraid what you said is pretty spot on. It's not the students but the training schools. The students are a lot more liberal and more accepting.
Universities are a lot more welcoming.
At the same time, I do get a bit annoyed with non-native speakers whose English pronunciation is so bad that I have trouble understanding them get jobs, mainly because these same training centres can get them cheaper.
I will give you a good example.
I was teaching a class in a training school. One of the students from the training department of his company was very excited one day he had met a foreigner from the Bahamas and wants him to teach English at his company even though he could tell his pronunciation was really bad. I asked why would you do that? He said he is cheap and we can just play with him.
Now I think it comes down to choice. I would be quite happy to learn Chinese from a non native speaker especially at a low level if I knew his/her pronunciation was good and could teach me language structure but there is no way I would learn Chinese from a non native teacher who couldn't.
Totally understand your frustration