Numerous sources confirm that this is true, or at least, that it is true that former Facebook employees have spoken out and admitted that Facebook does in fact censor news feeds on Facebook filtering out conservative news.
Considering the severity of these allegations, it is highly unlikely that the Facebook employees lied. Even though Snopes says “unproven”, in fact there is far more evidence for this than some of the “true” falsehoods on Snopes. The body of evidence supports this claim.
Moreover, Facebook is now being questioned by the U.S. Senate regarding the allegations.
Former Facebook staffers say conservative news is deliberately suppressed | Fox News
US Senate launches inquiry over Facebook’s alleged political bias in Trending news list | RT News
Did Facebook bury conservative news? Ex-staffers say yes. | The Washington Post
Former Facebook Workers: We Routinely Suppressed Conservative News | Gizmodo
Yes, it is apparent that Snopes is utilizing their clear and outspoken liberal bias to manipulate Snopes readers.