Exactly. Blameless and non-violent language can streamline communication. It does this by removing any trigger that would make your communication partner feel defensive. Needlessly emotional and charged language is sure to distract from the subject at hand. When you use calm language, there is only one thing to focus on: the content. When you call someone's code garbage, there are now two things that that person could focus on -- the content and the tone.
To me, it is completely reasonable that the original author might have made a mistake like this. After all, when he shared his findings it seemed like he had found something interesting to me! Many people on this very site commented positively on his efforts. There is nothing "garbage" about the code that he wrote, it just doesn't quite do exactly what he thought it did.