Late edit: 1) bold and capitalize 'allegedly' above; 2) in the response linked in a comment below, on p.2 lines 7-8, Meta claims the [fact check] labels constitute protected opinion; 3) it could easily be a libel non-case, especially as it is Stossel.
My impression is that Meta's distancing move ("third party" fact-checkers, with label/pointer linkage) is more solid than a claim, say, "I am merely the owner of the safe and the combination, your Honor, not the contents themselves." However, if someone such as Stossel wants to pierce the veil with regard to 230, so to speak, it seems a good question whether a prominently linked "fact check" has the same ontological/moral status as any uninvited third party post.
My impression is that Meta's distancing move ("third party" fact-checkers, with label/pointer linkage) is more solid than a claim, say, "I am merely the owner of the safe and the combination, your Honor, not the contents themselves." However, if someone such as Stossel wants to pierce the veil with regard to 230, so to speak, it seems a good question whether a prominently linked "fact check" has the same ontological/moral status as any uninvited third party post.