United States | News & Politics

Edward Herman and Noam Chomsky answered this question in quite a lot of detail in "Manufacturing Consent." Short answer, the systems of media in the United States have been successfully co-opted by the government and military, and a variety of overt and systemic factors combine to make anything that's presented in any media that grows beyond a certain size inevitably support the interests of the ruling class. There's a much more detailed, although still high-level answer, in Wikipedia's summary: https://en.wikipedia.org/wiki/Manufacturing_Consent#Propaganda_model_of_communication

The landscape is different now that mass media is being replaced by corporate social media, but it took surprisingly little time before the same systems of control began to function in the new paradigm, and impact what viewpoints and organizations are censored and which ones are boosted in modern social media.