Perhaps I should explain our thought process. There were at least half a dozen major web publications today putting out variants of this indignant post about "Facebook's unethical experiment". Did all these authors suddenly develop a passion for science ethics? Of course not. It is simply the internet controversy du jour. Those have never made for good HN stories, and the policy has always been to penalize them, because otherwise they would dominate the site.
In cases of pile-on controversy like this one, when the original story has already been discussed on HN—which is pretty common, because HN users tend not to miss a day in posting these things—we usually mark the follow-up posts as dupes unless they add important new information, or at least something of substance. Does this article add anything of substance? It didn't strike me that way, but arguably it does.
As for the PR fluff piece you think is on the front page, why haven't you flagged it? It's impossible for us to catch (or even see) all such things. We rely on users to point them out.