This is the unspoken part of these sorts of criticisms of social media--people aren't responsible enough to form their own opinions. I actually believe that's the case, but I also believe in free speech, and I'm not sure how to reconcile those things.
Such wrongness is only allowed to foster when it eventually becomes impossible to challenge it publicly. Of course alongside that freedom also comes my freedom to publicly reject the idea that 2+2=4. It seems to me that in modern times the problem has not been so much people coming to 'wrong' opinions, but people being unable to accept others having such opinions. Then in the fruitless and effortful battle to convert the pagan, divisions are only widened and beliefs hardened.
Perhaps the issue is not one of wrongness but intolerance of wrongness. I suspect we all get this feeling when we see something we believe to be wrong of "Agh! If he only knew what I knew, he'd never think this way." Of course the catch is the other guy is also often thinking the exact same about you.
Too add to that, if those who do express their own, dissenting, views get pilloried for it, who is going to want to start learning to express theirs? The usual answer is the thickest skinned and the most extreme.