This is a world-wide phenomenon, not just with CoVid but with any kind of rigid belief system. Lots of terminology for this kind of thing in anthropology, but basically these belief systems are "non-inclusive" (meaning you are either with them or you are against them and you can't join easily). They are "corporate" in their beliefs (high degree of intra-group consistency in beliefs - everyone believes the same thing, so that everyone they run into reaffirms their beliefs).
You must accept their basic premises and study on them a long time (they will tell you) before you can truly understand them. In this case, many core pandemic/CoVid denier beliefs have to do with conspiracy theories, the idea that there's a "deep state" and a giant conspiracy against the Bible, God and Jesus's second coming.
It's prudent to be wary of belief systems that basically tell all outsiders "You simply cannot understand the Truth unless you join us" and joining means "unquestioning acceptance of everything in the belief system." A person has to humble themselves before this new belief system, take it on faith, accept it completely and seek help if they ever have doubts (by calling upon True Believers). Willa Appel has written an entire book on this. If you're raised in it, it's hard to get out.
Tons of these kinds of belief systems in the world, through all time. If you ask hard questions of them (or, even, what would appear to be easy questions to a non-believer), they will tell you that you need to study more and learn more and believe harder. That it will take you "years and years" to really get it - that you need to allow them to just tell you the answers in the meantime but in future, it will all "come together" and you too will believe as they do.
Empirical evidence never enters in.