You're exactly right and it's terrifying. I have experienced this in person a couple of times. You apply the simplest argument and it instantly becomes apparent they have isolated themselves from contrary option their entire lives. They have never been made to realise how wrong and how easily disproven they are because these echo chambers will pat you on the back for literally anything. What's worse is that they become so certain they are right that it's impossible to convince them otherwise. They just reject your argument, however undeniable, because how could they possibly be wrong? Obviously I must have made a mistake. It wouldn't be so bad, though, if they weren't so arrogant and condescending in their attitude. "Oh, sweety, I'm afraid the science [citation needed] disagrees with you there."