A comment consisting of nothing but "got any sources for that?" is certainly "rather unsubstantive". But that is not why I replied to it. Had that been the only thing wrong with the comment, I wouldn't have. It was the following:
> Edit: lol, downvotes for asking for sources? "Hacker" "news" is just full of gems!
... that caused me to reply as a moderator, because that breaks more than one of the site guidelines, as well as being lame. This is routine moderation.
Both the original commenter and now you have given a distorted version of what happened there, as anyone who looks at the original thread can easily see. If that's what you have to resort to in order to come up with examples of moderator abuse on HN, we must be doing pretty well. Better than I'd have expected, in fact, given that we've posted 38,000 of these and no one bats a hundred.