
Of course, what makes a comment “positive” or “negative” is a very subjective thing. Since Facebook is a global site, and what is acceptable in one culture is offensive in another, the company generally relies on a combination of software algorithms and notifications from other users to identify inappropriate behavior. This seems to show a glitch in that system.
Is This Censorship? Facebook Stops Users From Posting ‘Irrelevant Or Inappropriate’ Comments | TechCrunch
Seems like social signals can be manipulated if you get creative with this...