Re: If the tone is wrong the content is lost
There's also a social issue when contributors come from a wide range of social backgrounds and cultures. What is showing a bit of mild exasperation by some, is felt as a serious attack or insult or humiliation by others. (Translation between a second language or "lingua franca" and a mother tongue is likely to make this worse. Words can have overlays of meaning in one language that are absent in another.)
My own approach is always to wait and see. Actions speak a lot louder than words (or alternatively, supply the context by which the words should be interpreted). I don't care if someone calls a spade a spade, and I've called myself a fscking idiot enough times that I won't be overly bothered if someone else does -- provided there is some justification (which I don't necessarily agree with), and provided they're not trying to denigrate everything I do regardless of its quality.
There's probably also a reverse problem, if someone's maximum expression of disappointment is so gentle that some other person doesn't register it at all ... until words have failed to convey the message, and they become the subject of an actual act of rejection.