There is also a kind of reverse virtue signaling to each other about how "edgy" they are when it comes to being steeped in/buying into what they think is insider knowledge...

For example, the ones that claim they are flat-earthers - I honestly think many of them might not really believe it, but use it as a way to play the kid skipping science class and smoking out behind the school, basically as a way to raise up their middle finger to annoy the people they think are just being schoolmarms: "you're not going to tell ME what to believe, I did my own research!"

The reality is, anyone they think of as a schoolmarm ("normie") just mostly would rather ignore these asshats, and just roll our eyes at their juvenile and backward ways. Sadly, what these idiots do in large groups ends up harming everyone - e.g., not vaccinating, being terrible at reasoning skills, basic numeracy and literacy, while at the same time being able to vote for the Republicans.

Yep, this pretty much nails it.

The conspiracy makes them feel a sense of importance that they can't get in any other aspects of their lives. It is sad, these people cause real harm to those around them with these fantasy worlds they buy into.

Telling them they are wrong, often just feeds the delusion; because you don't know the secrete, this makes them feel more of the same, feeding the conspiracy further.