Good article, and I certainly agree we are facilitating echo chambers. However, I believe there is a measure of personal responsibility here as well. One has to look at what the other side is hearing and saying. It’s really important not to simply dismiss the other side. We all have to dig a little to understand how people could vote for someone so ridiculous. Because that’s what both sides fervently believe about the other.
By the way here is a TED talk from 2011 on exactly your point, what Eli Pariser called “filter bubbles”.