Echo chambers / Safe spaces.    The left is full of people that say the same stuff and suppress free speech.  So they don't hear people saying things like "Trump hasn't really been any different from any other president", which would result in instant social exile.  Now the right has this too, but not to the same extent.  So the extremes become more and more polarized, resulting in more and more "100% agreement".  So we will see constant overconfidence in the next few elections, unless SJWs as a social condition completely disappear.  Because they completely are ignoring the fact that groups of people are leaving their movement.  Events like Gamergate and BLM are effectively steering large voting blocs conservative. When people are willing to say things like "It's a free country" again, overconfidence in politics will be on the decline.