Great point - a possible explanation for a wide range of phenomenologically bizarre viewpoints (e.g.: anti-vaccers, birthers, chem-trails, creationists, etc.)
Most of your examples are social membership tests. You have to publicly say "XYZ" to join the club, where "XYZ" doesn't necessarily mean anything, but joining the club does. Like saying Abracadabra to open a door.
(Spoiler alert don't read till the 26th)
Do you believe in Santa? I believe in Santa. Oh how nice you also believe in Santa. Aren't we all happy members of our club? It would be so antisocial for someone to say Santa doesn't exist, because then how would we tell who is in our club? This is the best club ever. Santa? Who's that? We just talk about him to pledge allegiance to each other, we don't actually care about fat dudes in red suits.
Can you expand on this? Are you suggesting that most of the people who say these things publicly don't actually believe them but are instead just trying to fit in to a certain social group?
I'm not VLM, but yes, peer-pressure in another guise. Just think about your attitudes and beliefs on (a) handgun ownership, (b) creationism and (c) Israel. It's very likely that if you're in a social group with strong homogeneous view on one of these items, that there will be a matching "party line" on the others - even though they're completely unrelated. Chances are low that you'll argue the point, you'll probably just stay quiet - but many people will enthusiastically take that party line as their own.
I think that's just groupthink. People tend to act on their beliefs about things like vaccines, Israel, and handgun ownership.
Of course, it's one of the earliest results in psychology that social conformity has an influence on people's beliefs, even on readily accessible questions like whether line A is longer or shorter than line B. To me, if somebody professes a belief, acts on that belief, and works to convince others of that belief, then they effectively hold that belief.
