Many foreign teachers in China are distrustful of each other. They find it difficult to get along with one another, and do not make an effort to do so. Whenever they have differing views, they will criticise one another bitterly.
Contrast the behavior of Chinese working abroad. They will help each other whenever possible, and become friends.
Maybe this culture difference is due to the fact that Chinese culture is far more group-based than Western culture.
The venom in some of the posts on this board is here for all to see. I've been told that there's much worse that thankfully has not been accepted by the board moderators, who are kept busy rejecting much ruder posts than those that we are permitted to view.