The problem is that no automatic method we have now will catch context. There is a difference between "Jews were murdered by Germans during war" and "Jews destroyed German economy before the war" that will not be recognized by any machine we have nowadays. The first is true, the second is bullshit, how algorithm can now this?
More, even if Facebook employees humans to do moderation still for some contractor from Asia "Jews destroyed German economy before the war" might not be easy to verify. For a contractor maybe Jews did that, who cares, I have 20 seconds to moderate this and move to other post. The same way if I was asked to moderate some historical details about India-Pakistan conflict or other historical facts about Asia, Africa I have no knowledge about at all.
I was reading quite a lot recently about war in Angola and still I have doubts which side was "good" and which was "bad", besides that people who lived there were hurt in the history like almost no other nation.
Even worst. Some, especially historical, facts are judged from different perspective. For instance in Poland Napoleon Bonaparte is a mythologized person that brought hope to Polish hearts to get back their homeland [1]. From the point of view of someone from Austria or Italy, well, Napoleon is considered to be far from hero.
We don't have to go back that far in the history. US intervention in Afghanistan or Iraq can be seen differently depending on somebody views.
How to moderate all this?
[1] Fun fact: not a big surprise that Napoleon didn't give a crap about Poland, he even refused to give them a proper King at the short time he could (he has chosen some Saxon prince). At the end, when Napoleon lost, remains of Polish military units were sent to Haiti to help France to maintain their colonies. Many Polish soldiers died from tropical illnesses there, many joined Haitians as they saw that those people were fighting for their freedom like Poles were.