This is being challenged by Texas and Florida, which have passed laws to require a level of free speech on the platforms. The platforms argue that their editorial control on what they host is itself protected speech (in the same way that magazines deciding what articles to accept is).
The states, for their part, argue that the media companies are more analogous to common carriers, which can be subject to non-discrimination laws.
The case was just heard by the supreme court, so we should get a decision at some point.
The right to free speech only means you can't be prosecuted for what you say. It does not compel any private entity to distribute everything that you want to say.
It is a much broader protection against government retaliation than just "cannot be prosecuted", but it is a protection against the government, and it includes protection against being forced to endorse and relay others' speech. Compelled speech is the opposite of free speech.
Just because they are not legally liable for what users post, Congress did not want to prevent platforms from going beyond their minimal legal requirements if they so chose.
The alternative us a law that says "It is unreasonable for us to expect you to perfectly police your users; but we will hold you liable for imperfectly doing so".
Is it merely the fact that encryption blocks the carrier from knowing what the line is used for? Or said another way, should AT&T have the right to terminate a user's service if they were certain a user was posting, say, white supremacy?
Here are go again.
Are we going to have to have the same argument that's already been on HN a million times about whether or not "free speech" means compelling a private company to let you use their platform for speech?