多瑙你说的这些， 我以为都是sentiments

不过我来说一个美国的转折点吧， 是里根政府不再实施The Fairness Doctrine

https://www.reaganlibrary.gov/archives/topic-guide/fairness-doctrine

The Fairness Doctrine mandated broadcast networks devote time to contrasting views on issues of public importance. Congress backed the policy in 1954 and by the 1970s the FCC called the doctrine the “single most important requirement of operation in the public interest – the sine qua non for grant of a renewal of license.

The doctrine stayed in effect, and was enforced until the Reagan Administration.

这是老美们容易有information cocoons的一个重要原因之一