I think (suspect) the trick FB is using is not unlike Uber / Airbnb where they fall just outside regulation. Meaning that sponsored content on FB is just "self-regulated"
[1] https://www.theguardian.com/business/2014/nov/03/hyundai-and...
The ones in Australia and in the UK come to mind and have serious bite in confronting offenders.
Add to that that ads in newspapers are clearly identifiable as ads, while this is much more intermingled in social media.
Also can you back up your statement about not fact-checking before anyone claims otherwise ?
Unfortunately more people consume Facebook than others, so its a prime target.
Also I would point you towards another article :
https://www.reuters.com/article/us-usa-election-advertising-...