Well, with the decline of newspapers there should be plenty of unemployed journalists who'll be happy to spread some knowledge around FB for a moderate fee?
Or - this thought scares me the most - FB actually doesn't care about facts?
Well, they surely are. The stupid part it's that they are opinions of people that have no business having an opinion on such matters, them having no related qualifications, no education, no access to facts, not doing any research or having any idea how the research is done at all - and their opinion is taken as one trumping the opinion of the actual experts in the field. Out of all possible opinions Facebook chooses the worst to listen to.
Google and Facebook are a direct cause of the decline in the quality of newspapers and journalism in general through their intentional strategy to capture as much of the value from news as possible, even though they created none of the actual content.
This means most newsrooms can't afford as many editors and fact-checkers, can't dedicate journalists to complex subject areas, can't afford to have journalists spending weeks or months on particularly complicated and deep stories, etc.
They surely knew what the consequences would be of starving newsrooms of income, yet went ahead anyway and didn't bother to even think of let alone implement alternative models to preserve valuable news.
Facebook cares about advertising revenue. They only care about "facts" when content posted by users causes advertiser boycotts, or attracts unwanted attention from powerful politicians.
Journalists dont exist to spread knowledge. They exist to spread ideologies.
I challenge you to find a point in human history where "journalists" weren't putting their fingers on the scale. Look at the journalistic antics of someone like Benjamin Franklin for instance.
Or - this thought scares me the most - FB actually doesn't care about facts?