"Political censorship" by "private companies" is not arbitrary. In light of historical facts and contemporary litigation between private- and public-sector corporations and a state's agents and divisions, one ought to discard the conceit of "free market" conditions in order to apprehend when or why a company's directors (people) enforce public law and which people exercise actual authority and means to compel compliance with public law.

Read for example Twitter's public policy statement again. A disclaimer therein acknowledges the authority and means of US government ("intelligence community") to compel its compliance with public law. That acknowledgment is not trivial.

That censorship expresses public law is not a trivial distinction from so-called common law, shunning, shaming, boycotting, and self-censorship said to restrain trade (of anything) between individuals.

Violation of the former imprisons and does sanction execution of the "offender".

Diversity is the key to economic and political evolution.