I think you're misunderstanding Poole's stance on this. Zuckerberg seems to be pushing for a huge reduction in anonymity - maybe to the point of removing it altogether. That is definately because it would benefit him directly.
Poole, though, is just saying that it would be a mistake to assume there's no value to anonymity. He's clearly not saying that everything should be anonymous, since, as pointed out in the article, he's also creating a new site that utilizes FB profiles.
Facebook's popularity is driven by attaching your real life to an online identity. 4Chan's success is driven by total anonymity.
That the two founders have diametrically opposing views on anonymity is not really surprising. There's certainly merit to both view points.