It is 100% untrue that the government is the only entity required to respect freedom of speech. This issue was settled in 1979, in response to the civil rights movement, when congress passed a law that provided people with legal mechanisms to ensure that other private persons respected their constitutional rights.
Every person who, under color of any statute, ordinance, regulation, custom, or usage, of any State or Territory or the District of Columbia, subjects, or causes to be subjected, any citizen of the United States or other person within the jurisdiction thereof to the deprivation of any rights, privileges, or immunities secured by the Constitution and laws, shall be liable to the party injured in an action at law, suit in equity, or other proper proceeding for redress, except that in any action brought against a judicial officer for an act or omission taken in such officer’s judicial capacity, injunctive relief shall not be granted unless a declaratory decree was violated or declaratory relief was unavailable. For the purposes of this section, any Act of Congress applicable exclusively to the District of Columbia shall be considered to be a statute of the District of Columbia.
The myth that, “Censorship is only unlawful when the government does it,” is likely perpetuated by Section 230 of US Code 47, which unconstitutionally grants internet publishing platforms immunity when they restrict freedom of expression.
(c)Protection for “Good Samaritan” blocking and screening of offensive material
– (1)Treatment of publisher or speaker
No provider or user of an interactive computer service shall be treated as the publisher or speaker of any information provided by another information content provider.
– (2)Civil liability
No provider of an interactive computer service shall be held liable on account of— (A)any action voluntarily taken in good faith to restrict access to or availability of material that the provider or user considers to be obscene, lewd, lascivious, filthy, excessively violent, harassing, or otherwise objectionable, whether or not such material is constitutionally protected; or (B)any action taken to enable or make available to information content providers or others the technical means to restrict access to material described in paragraph (1).
How the American public came to interpret Section 230 as something that protects us from censorship, when it does exactly the opposite, is beyond me.