For example, "thousands lose their jobs due to minimum wage increase". Is this true or not? Well, some schools of economic thought will think its true, and some will not. Some might say the jobs were lost because there was an increase in automation and some might think the increase in automation was caused by the minimum wage. I truly hope that facebook doesn't try to fact check statements like this.
There is inherent bias in the way we look at the world.
i.e. "Assad bombs his own people" vs "Assad continues the fight against ISIS and Al Qaeda" Although an argument could be made that these two statements are not mutually exclusive, they are saying different things. It is quite possible that one will pass through the fact checker and one will not.
Facebook is such a huge source of information, it makes me very concerned when a select few organizations have the ability to discredit information across the entire site.