The "bubble" expression I've only ever encountered used by people from a rightish perspective to complain that other people aren't listening to them and that their perspective isn't the completely dominant one. Whereas people of the opposite view always know what the opposing view is - it gets shouted at them a lot - they just don't agree with it.

Anti-vaxers and flat-earthers might be called "bubbles", but then so is the pro-vax round-world view. After all, if you only ever read round-world media, aren't you closing your mind to alternative facts? /s