Canada

Some of it is pure misinformation - the very thing they fear, getting weaponized against them. There’s a way to present things to people that sounds very convincing to someone with weak critical thinking and/or without empirical research experience. These people typically will focus on the few pieces that validate their beliefs and throw the rest out as lies/conspiracy/garbage/etc. It gets kind of dangerous when they hit peak Dunning-Kruger and they totally refuse to hear reason, they usually need some kind of major tragedy close to them to question themselves lol…

I guess some of it might be some sense of belonging. There may be a part of it that is purely about validation from peers.

I’ve also had many friends over the years who didn’t get vaccinated as children over religious reasons.