If you had cut out the "Admittedly I stopped reading the article when I got to" part of your comment, you probably wouldn't have been downvoted. I think the general perception is that it's difficult to add to the discussion of an article if you didn't even bother to read that article, especially when your comment merely echoed the article.

I, too, think it is that particular phrase, and I disagree with the sentiment of downmodding this kind of admission instead of actual content.

I've seen this elsewhere - if someone says they're being sarcastic, they're downmodded to hell... but people in the same thread saying the same thing in the same sarcastic manner, but without the admission, are left alone.

I find this inconsistency annoying - it appears that downmod-friendly HNers are more interested in making a pretense to politeness than actually moderating content. It only takes a single dissenter and your words are already diminished on the page.