Classical conditioning. Seriously.
People like us -- folks who took covid seriously -- spent a year or so wearing masks more or less religiously. We didn't get covid. That's an entire year of our lizard brains learning "my mask keeps me safe." Getting vaccinated is great because it makes covid not so scary any more, but our lizard brains aren't having it. Those masks kept us safe for a year, so it stands to reason that taking off my mask is the equivalent of drinking a liter of coronavirus and will make me suffocate to death within minutes of letting it slip down under my nose. Obviously that's silly and irrational, but that's how our lizard brains evolved.
I definitely experienced this myself. From spring break 2020 to February 2021, I went to the gym zero times. I run 4-5 days a week, but I was determined to avoid the gym even when it reopened, because there's just no way that a gym is a safe place to be when there is a novel respiratory virus floating around. Well, in late February we had a very cold cold snap, and I ended up going a couple of times first thing in the morning (very few people around, air has been turned over overnight) to get in some minimal mileage. Taking off my mask in a public setting felt really weird and
dangerous. A couple of months later, after vaccination I had the same feeling the first time I went to the store without a mask -- I felt irrationally vulnerable walking around with two shots of Moderna flowing through my veins and I felt like I kind of wanted that security blanket for my face back. But I know about conditioning and I recognized it for what it was. After a couple of days, I was over it. It was just a matter of realizing "My brain has irrationally formed a link between 'wearing a mask' and 'being alive' that doesn't make sense any more -- time to show my lizard brain how science works." I think some of the more zealous pro-mask people are just stuck in security-blanket mode, and will be until they're dragged kicking and screaming back into normal life. Then they'll be totally fine after a week.
As a runner, I feel obliged to add that so-called "taper madness" experienced by marathoners is the same thing. During marathon training, you simultaneously feel tired and sore and also gain fitness. Your brain inevitably comes to associate "being tired and sore" with "being fit." When you start to taper and all that soreness goes away, runners irrationally fear that they're also losing fitness. Just being aware that your brain can trick you this way is all it really takes to short circuit this process.
