I guess the way it works is the facebook “community” causes articles to “trend” by resending them.
Facebook editors were looking at what the “community” was causing to “trend” and removing articles it disfavored from the “trending” feed.
Or something like that.
Or, added more of what they preferred, in an astroturfing effort.
Basically they were “rigging the vote”, “cooking the books”, “adjusting the numbers”, etc. All with no transparency and all pure propaganda and lies; all for a profit.