Echo chambers are real, as we all become more ingrained in our positions and can easily tune out things we dislike we become obsessed with a false sense of reality.
I like Medium, but it is so arrogantly anti-Trump (and I am too) that it gave everyone a false sense of security about the real prospects of this election. People who voted for Trump were tuned out and we took that to mean they didn’t exist.
I was utterly surprised that he won, but I clearly shouldn’t have been. I knew he would carry my state, handily, but I thought enough voters couldn’t stand him to offset any potential polling errors in his favor. I shouldn’t have used conjecture in that case.
But the reality is that Trump was never that far behind, we were just that misinformed and made it worse by pigeon holing ourselves into a vantage point that made us look correct from our angle — confirming our biases.