It is the small kernel of truth that makes the lie succeed.
Consider the 'Rona. A small kernel of truth – some people were getting sick – used to propagate the lie that everyone was at risk of getting dead. Unless, of course, they accepted a one-size-fits-all regime of "lockdowns" and "practiced" patently silly (and incredibly dehumanizing) sickness kabuki, including the wearing of something over their faces – it didn't matter whether it served any medical purpose – so long as people turned themselves into NPC people by effacing their faces.
America became a kind of sickness gulag. Millions of people have been turned into possibly permanently damaged weaponized hypochondriacs, obsessed with sickness and death – because of a concerted, deliberate campaign of mass hysteria intended to create the impression of mass death impending. All of it premised on the nugget of truth that some people were dying . . . almost all of them people already dying from other things, such as old age and cardiac/respiratory problems, possibly pushed over the edge by the 'Rona.