I assumed it was self-evident that these claims were unconvincing [..]

Then there's no need to comment. Comments in places like these add value when they contain information above and beyond what is already contained in the article. If your assumption is correct, your comment simply states what everyone already knows. If the assumption is incorrect, your comment doesn't provide any argument to convince others that your claim is correct and the article is wrong. In either case, your comment doesn't add anything. There's no need to point out the blatantly obvious, unless to explain why it is blatantly obvious to someone for whom it isn't blatantly obvious.

What threatens the signal-to-noise ratio of HN is that more and more people start making unsubstantiated claims concerning articles. They may be right, but I, as someone with only casual knowledge of a given subject, will never know. People responding only to state their opinion, without supporting it with possibly convincing arguments. I don't feel those kinds of comments are worthwhile.

  And had you bothered to look up the author on Wikipedia

My point is that your argument was too broad and this individual author's credentials are inconsequential. Even if reporting in personal finance is awful in general, then after your comment, I still didn't know why this piece in particular is awful.