I have to admit that in the original email exchange posted that the blog post we're not linking to was referring to, I did not think the author was rude enough to warrant the extremely rude reply from the agent. Both of them seemed to have lost their patience or had a bad day -- or whatever. One of them needed to step back and breathe deeply and suck it up and be the better person.

However, I totally disagree with you that rude people are rarely successful -- I have run into so so so many people who are rude and awful who are really successful. Sometimes rude people are just good at what they do. (Usually, in my personal experience, the successful rude people are white men who work in academia or for corporations. YMMV.)