It's a combination of things; propaganda,, normalization, but I think the most interesting and probably least discussed is the security blanket effect (not sure what the proper term is)

lemme give you a fictional example. Linus is probably the smartest character in the Peanuts comic strip (or at least he's portrayed that way), and yet, even though he's too old for it, he carries a baby blanket with him everywhere. it's not logical, it's not sensible, but it makes him feel more secure and safe. he actually becomes distressed if he can't find it, or even violent if someone tries to take it from him.

It's similar with these people. While not all of them are the smartest people int he world or anything, some of them are fairly intelligent, but they were all gullible. (sidenote: do not confuse gullibility with stupidity. while they are similar, they are not the same thing. the smartest person in the world can be fooled by a skilled con artist under the right circumstances)

so these people spent three years clinging to the idea that the jabs and the masks would protect them from the Big Bad they'd been told to fear. it's become comforting for them. it makes them feel safe, even if logically they may realize at this point that it's actually a threat to their health.

...and then you factor in all the calamity that's happened in those years (financial crisis, banking collapse, possible war with russia/china...), and you realize these people are desperately clinging to the jabs and the masks for comfort, just like linus with his filthy blanket.

I don't know how you combat that, but that's what I see.