Some other poster, Magister, I believe, said, being able to speak mandarin shouldn't be a prerequisite for the job; I never said it should be

What I actually said is that speaking mandarin shouldn't be a prerequisite for fair treatment by your employer (do you disagree with this?). That was in response to your comment that suggested foreign teachers bring problems on themselves by not speaking the language.

There are many reasons for learning Chinese and as a topic of debate this has been covered many times over the existence of this board including several times in the last couple of months. However, learning the language to avoid contempt from Chinese colleagues (as you stated in your original post) hardly seems a good reason. Nor do I think that it would be particularly effective at solving poor relationships between foreign teachers and local management because the reasons for this contempt generally run far deeper than just the chinese language skills of the ft. It's also worth noting that some schools (particularly training centres) would actually prefer to employ newbies with little or no language or cultural experience of china (easier to control). By in large the management of such places are not looking to become friends or extend cultural ties, what they are looking to do is make money. Do that for them and you'll generally find that you have a more pleasant experience working for them regardless of your ability to speak mandarin.