The whole situation is a result of a common communication problem, applied twice. Simply: we see ourselves in the gaps. i.e. readers assume the writer shares

The whole situation is a result of a common communication problem, applied twice. Simply: we see ourselves in the gaps. i.e. readers assume the writer shares their own values/goals. From that default, we build our mental model of the writer, generally by recording deviations. Until a deviation is recorded though, our assumption is that there's agreement. That's why new information that violates our mental models can seem so surprising, even when we have no good reason to expect otherwise. The common advice to 'never meet your heroes' is direct result of this dissonance. Seeing the reply as an insult required Joel to assume the writer had the same values Joel did: a mistrust of sales and marketing. Ergo: any congratulations on an effective sales pitch must be a sarcastic insult. And in writing that reply in the first place, the author clearly assumed Joel had the same values he did. That is, that the article was an intentional (and commendable) application of marketing and that Joel would appreciate an 'atta boy' from a peer. Emphasis and emoticons can go some way into clearing up these misconceptions. But not even face-to-face communication really solves the problem.