Personally the only times when I got back-stabbed at work were by Canadians, but I don't go around making conclusion about Canadian culture being backstabby.
If 1 in 10 Chinese you met are manipulators, that means 9 out of 10 are NOT honest/manipulative, how can you then go conclude "in Chinese culture 'any means necessary' tactics are considered smart and fair game as long as they work."?