I think the networks way over-adopted the spirit of the FCC's Fairness doctrine (1) and the equal time rule (2). It's so easy to build controversy and call if "fair and balanced", which drives up ratings while suppressing the evolution of any meaningful progress in any of the affected areas.
I think a lot of it has to do with CNN and cable news presenting politics as sport. Jon Stewart's take down of Crossfire is still relevant and if anything, CNN doubled down on what Jon was criticizing: https://www.youtube.com/watch?v=aFQFB5YpDZE
(1) https://en.wikipedia.org/wiki/Fairness_Doctrine (2) https://en.wikipedia.org/wiki/Equal-time_rule