And for the record, intent is the only thing that actually matters in this discussion, as the only real damage that has occurred is towards Martin's reputation, which more than likely was Zed's (specially knowing his belligerent tendencies) intent.
The person wrong was Edme. The person wronged was Shaw.
Absorb these facts.
The person who tried to tell the person he wronged that he hadn't actually done anything wrong was Edme. The person who twittered about the person he'd wronged being a douchebag was Edme. The person who continued and escalated the confrontation, instead of apologizing, taking his lumps, and STFUing, was Edme.
Absorb those facts.
This story does NOT start with Shaw's first message as some sort of aggression. It starts with Edme and it continues with Edme, no matter how you try to recast it.
Now, if Shaw's "tendencies" were leading him to try to ruin Edme's reputation, I think he could have accomplished that much easier by making a long blog post about how Edme is an asshole, instead of a blog post that tangentially mentioned that some unnamed people were trying to "port" his book, why that was a bad idea, and how to properly go about making a version of his book.
On the other hand, Edme tried to publicize the exchange. He posted it on HN to cold disinterest and a flag-killing. If anyone was trying to hurt anyone's else's reputation, I think it was Edme himself. That Edme's reputation will probably suffer more that Shaw's is just funny.
Martin's actions after Zed's response are inexcusable. But that doesn't mean Zed wasn't being rude.
I subscribe to the "Don't be a douchebag" philosophy, and I think both Martin and Zed were being douchebags. BUT Martin wasn't being a douchebag when he copied the book, he was just being ignorant (and breaking the law).
If I made a mistake like this, I would gladly take down the work, issue a public apology, and submit salvageable content to the person doing the Ruby version of the book, but in no way am I going to be talked down because I wanted to do a good thing as if I was in the same league as a plagiarizer. It could have been a win/win situation for everyone.