Increasingly I think arguments are in public and recorded for posterity, making the social cost of a mistake (or being poorly informed, etc) much higher. Given that, I think we're seeing many arguments that are more about group belonging and performance rather than a genuine effort to learn via debate and dialog.

Throw in some radical oversimplifications and that's a pretty strong recipe for polarization. One that's actively cultivated and amplified due to media profit incentives. Unfortunately it's a vicious cycle that seems to make us dumber and oversimplify even more.