Original sentence: Conservative commentators have also criticised American news networks such as CNN, CNBC, MSNBC, and the Big Three: CBS, NBC, ABC, of systematic liberal bias, though the viewers of these many channels despute these claims
Edited sentence: Free speech, when suppressed by one group, finds a way to make itself heard in the marketplace of ideas.News networks such as CNN, CNBC, MSNBC, PBS, and the Big Three: CBS, NBC, ABC, have long held a monopoly over the airwaves and cable systems and biased their news stories from a primarily liberal worldview.This monolithic and selective approach to mass media -- presenting only one side of a news story to the detriment of the facts -- has given a rise to the phenomena of FOX News, talk radio, and internet Blogging or Weblogs