There are a lot of Facebook employees on HN, just like there are a lot of Google employees here. Those employees will do some level of astroturfing. Unless HN prevents us from voting on topics where there is a conflict of interest, it's hard to keep the bias out.

Facebook has made a lot of questionable or incite-ful moves lately (Fwd.us, Slingshot, many acquisitions without a coherent vision) while it's quality and usefulness to many has become of marginal importance.

This isn't 2009/2010, where Iranians and Tunisians were using FB to coordinate peaceful protests. Instead, fear of the encroaching security-industrial-complex revealed by Snowden has people concerned about posting stuff to FB.