The article is right for the same reason that horoscopes seem right, because it doesn't really say anything. To my knowledge, nobody intelligent was seriously suggesting that a sharp recovery was likely. His article then discounts that relatively absurd possibility and then states his belief that the market will either be U-shaped, flat, or decline with a double-dip recession.

Given that at that point a serious depression was pretty much ruled out as well, he basically said that all possible responses were, in his opinion, possible... and then people read it and thought "wow, that horoscope was totally correct."