> we pay more attention to dissenting opinions

You can see negatives without dissenting opinions. r/politics is full of negative comments but dissenting opinions are pretty rare.

But paying more attention to negatives has real world value. We should be paying more when someone runs into a theatre yelling "fire" than if someone runs in yelling "free cupcakes." One has much more devastating consequences. On social media the effects are less devastating and more demoralizing.