The subject of article is more or less how IV's reasoning is flawed. Picking a quote from the beginning and saying "that is flawed" is just echoing the bulk of the article. I would guess your downmodders think you're not adding to the discussion.
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.