Back again? Quite a volteface.
Simply asserting a statement does not make it a fact but It may well reveal a person's prejudices (I believe I previously mentioned this detail).
Application of Hitchen's Razor seems appropriate in this case.
Put simply 'That wihich can be asserted without evidence may safely be dismissed without evidence'.
The burden of proof lies with the person making the statment. There is no burden on others to prove a statment false. Manipulation of 'facts' relies on elements of FLICC:
1- Fake evidence (bulk fake experts, magnified minorities, fake debate)
2- Logical fallicies (ad hominem, 'slippery slope', misrepresentation, ambiguity, false equivelence, false balance, straw man, unfalsifiable statements)
3 - Impossible expectations (moving goalposts, anchoring, reframing)
4 - Cherry picking (anecdote, wishful thinking, quote-mining, outlier data)
5 - Conspiracy theories (contradictory, imune to evidence, overriding suspician, apophrenia, persecution complex, externalization of internal conflict)
In fact, even if provided with evidence, some people will continue to repeat a statement as 'factual'. They may simply be unaware that a statment had later been found untrue. Factors may also include the 24 hour news cycle, social media (the algorithm), self interest and peer pressure. The seminal Soloman Acsh conformity experiments showed that humans will conform with groups they are parts of, especially if deviation risks ostraicm. Each is coersian of a sort.
Gainsaying is not the same as rational argument, but your post does serve as an example of how uncritical people can be sometimes. That which aligns with a person's prejudices is accepted uncritically, it having the ring of 'truthiness'. But even when said statement is shown to be false, it retains it's truthiness and may be repeated for years; decades sometimes. I suggest much of this caused by the news cycle, (previously mentioned), social media, media manipulation and polerisation (again, I mentioned the'either/or logical fallicy AKA black-and-white thinking). Only a minority of people care to know what lies a politician told yesterday, they DO care what a that same politican says today. Sadly, this is part of human nature.
I suppose that the Sophists make a fair point in asserting that direct experience is the closest we can possibly get to certainty, but even then, there will always be a certain amout of doubt. But doubt is scary. Thus it is human nature to seek certanty.