Forbes has a pretty good article covering Politifact's issues related to their truthiness judging.
In 2008, Politifact rated as True Obama's claim that if you like your plan you can keep it. The Forbes article notes that the author of that truth-o-meter article didn't check with any health-care skeptics.
In 2009, Politifact changed their rating for the claim to 1/2 true.
In 2013, Politifact labeled it the "lie of the year."
Politifact's 2008 rating was "widely repeated by pro-Obama reporters and pundits, and had a meaningful impact on the outcome of the election."
So, was Politifact's wrong analysis of Obama's 2008 claims "fake news?"
Were they lying or just being too lazy.
When they judge Trump's claim that Obama was the founder of ISIS in the literal sense but don't rate Hillary's comment that Trump is a recruiting sergeant for ISIS at all, either literally or metaphorically, then yes, I'll claim that Politifact is lying or at least intentionally distorting the truth.
Facebook absolutely has the right to determine what gets posted on their site and people have the right to use their product or not. The government on the other hand has no business promoting censorship of anything, including fake news. Fake news isn't new and people have a personal responsibility to explore the "truthiness" of what they read, hear and see.