"There is no distinct left-wing media ecosystem that parallels the right in its internal coherence or insularity from the center." -- Network Propaganda (2018) The evidence keeps piling up but people are going to do "on both sides" social/cognitive balancing until we all burn.
P.S. @RogueNotary you would probably get a lot from this book. It speaks to the differing information ecosystem dynamics and is useful in explaining why the self-described centrist IDW folks seem to spend all their time sampling left-wing excesses over right-wing ones.