I think the idea of a "bubble" is less that "bubbles" don't exist in real life or that it's impossible to hear anything outside them and more that the internet

I think the idea of a "bubble" is less that "bubbles" don't exist in real life or that it's impossible to hear anything outside them and more that the internet makes it particularly easy to find communities offering mutual reinforcement and insisting it's everyone else that's wrong. Even for people who are initially only idly curious about whether anyone else has ever felt that way. This includes things you might have happily accepted you might have just made a mistake on (but I thought I remembered this documentary about Mandela's assassination...) when your real world social circle pushed back, if only it wasn't so easy to find other people that thought the same, and theories of why you are right all along. Usually with a lot of other baggage linked into you being right and everyone else being wrong Obviously this isn't always a bad thing: people also use the internet to discover that same sex attraction is actually accepted in places outside their community or that their government's position on a border dispute isn't universally accepted in environments where alternative views are legal to express. And it happens offline too (the original 'Mandela Effect' was apparently conceived by a bunch of paranormal enthusiasts in an offline environment). But if the Azeri vet is one of the few people in the world to not think what you're saying is complete nonsense, you'll be much more likely to find him online. Not all taboos are against stuff which is inherently bad to discuss, and not all beliefs universally held within a community are accurate. But a lot of fringe stuff on the internet is fringe for good reason, and even when such views are quiet widely-held "bubbles" suck in people who would never have had the motivation to seek out an offline group for discussing the coming race war or whose fault their lack of confidence in dating really was.