Anyone can buy stock in Twitter, ticker acronym ‘TWTR’. It is a PUBLICLY traded company! Yet they claim they are private? TOTAL BS!!!
That’s not actually an argument. The “public” in “public companies” refers to the fact that their stock is publicly traded on a stock exchange. The resulting stock (and therefore the company) is owned by private individuals. In First Amendment terms, it is not “public” and freedom-loving individuals should resist arguments that the word “public” means the same thing in both contexts.
A much more powerful argument is that they are a common carrier or are analogous to a public accommodation, both of which are subject to requirements of openness and non-discrimination.