there are a lot of things that don't add up on both sides of the ponzi / not-a-ponzi arguments.
i haven't read much describing this as possibly being an attack against bitcoin itself. we worry endlessly about defending against a 51% attack, but we put our head on the chopping block with this ponzi-like scheme. if someone were trying to smear bitcoin, a story describing the several million dollar "bitcoin ponzi" collapse would be something that would spread wide and far. can you picture the post-mortem reported in gawker? it will be written in a way where there is no sympathy given. like ... "guys the fact that it was run by a person called pirate should have been your first clue. all the markings of a ponzi were ignored. you deserved to lose ever penny you idiots".
that solves a few problems all at once. it takes money from the early miners and others with lots of bitcoins. ask a random person on the street and the majority of those that know anything about bitcoin will remember that it "crashed down to a penny" (because that is what the media told them happened, regardless of what really happened). "bitcoin really was just a big ponzi" will be the take-way from this once it makes it into the headlines. even though this has nothing to do with bitcoin digital currency itself, this is what people will remember and bitcoin will continue to have an "image problem".
we've forgotten that there are people who do not want bitcoin to succeed.
I would not worry too much. There are only so many suckers. Only an extremely stupid person will hand his money over to someone anonymous, claiming to get him 7% per week. That is so obviously ridiculous.
The Ponzi scheme will not garner any very large fraction of all existing bitcoins. And if you are worrying about the Ponzi operator suddenly selling his entire mountain of bitcoins, no, he does not have to do that, because he has already sold most of them. He is a rather evil scammer, but stupid he is not.
There may be a dent in the bitcoin value when the Ponzi scheme finally shuts down, which may happen soon. But I will not sell now. If the dent is strong enough, I will buy then. If more people think like me, the dent will be limited. I will certainly do my best not to let bitcoin sink below $5. We want stability.
The US Treasury's and ECB's own Ponzi schemes may well blow up in a few years too and will help bitcoin even more. Watch the poor euro owners flock to bitcoin already today.