What's the point in saying "private company" if 99.99+% of companies are private?
Is that statement sufficient to stop further nitpicking?
Almost every use of "private company" is in contrast to a publicly traded company. Except when people start talking about "rights", and then they're apparently using it in a different way, which I find very odd and ideological.
Is it?
Actually, no argument has been given why a government owned company couldn't block links to whatever the government wanted.
Different rules, laws, regulations, etc. apply to private sector vs public sector.
Specifically in this case, OP is implying that a theoretical public sector social network wouldn't be allowed to block linking to mastodon because of the second (EDIT: no, wait, first amendment!) amendment, but that Twitter is well within its rights since they are in the private sector. Whether that's true or not, I dunno.
I dispute that the OP was implying or even thinking anything about a theoretical public sector social network.
Like I said, I don't know how far the first amendment would or wouldn't apply in this situation. In any case, it would likely have to be tested in court.
I don't know how I feel about a well regulated Militia overthrowing the government to protect free software and open standards...
The government actually controls companies. In fact they wouldn't exist as legal entities without the government.
I feel there is a common misconception that "private companies can do whatever they want", belied by the existence of government regulation, but nonetheless a misconception regularly employed to dismiss antitrust concerns, for example.
They're aware of the concept of law but frequently unaware of specific laws. ;-)
“There are two commonly understood ways in which a company is considered public: first, the company’s securities trade on public markets; and second, the company discloses certain business and financial information regularly to the public.
In general, we use the term to refer to a company that has public reporting obligations.”
They’re talking about $TWTR, not Amtrak.