Theory of mind, perhaps? (Interestingly, people with autism often have problems with this too.)
It's a natural consequence of surrounding yourself with only people that agree with you. When you live in a bubble of self-affirmation, your view of reality starts to get warped to the point where you believe the lens of SocJuc, MRA, of whatever your ideological poison is, is the way the world actually is.
Of course, if the majority of your socialization comes in online form, I'd wager you already have a few strikes against you in the social skills department. And yes, I'm aware of the irony.