Freedom of Speech ≠ The Free Speech Clause
One key difference: The Free Speech Clause is about governmental restrictions on speech; freedom of speech is about restrictions on speech more broadly.
This is something of an obvious point, but it's worth repeating, it seems to me.
Lots of laypeople, in my experience, talk about private speech restrictions as violations of the First Amendment. They're not. Generally speaking, if you're kicked off Facebook, or fired by your private employer, or kicked out of your private club for your speech, that's not a First Amendment violation. (There are some complications involving, for instance, private entities following governmental commands, but those are rare.)
This is called the "state action doctrine": The Bill of Rights generally protects you only against action by the state, in the sense of the government (federal, state, or local), not against private parties. It applies to the Second Amendment, Fourth Amendment, and other Bill of Rights protection as well. It's important to know.
But it's also important not to overstate it, by confusing the scope of the Free Speech Clause with the broader principle of freedom of speech. The freedom of speech can refer to freedom from private entities as well as governmental ones.
That's nothing unusual: The right to property can refer to the right not to have your property improperly taken by the government and the right not to have your property improperly taken by private entities. The right to privacy can refer to the right not to have the government invade your privacy in various ways (contested as the scope of this might be) as well as the right not to have other people invade your privacy in various ways. The freedom of religion (or, say, the freedom to wear religious symbols) can refer to the right not to have the government abridge that freedom in various ways as well as the right not to have employers abridge that freedom in various ways. These are important rights; they're just protected not by the Constitution, but by state and federal laws, and sometimes by social or professional norms.
And there can be good reasons to protect freedom of speech (as well as other rights) from private abridgment as well as from governmental one. Private restraints on speech can interfere with self-expression and autonomy. Private restraints on speech can interfere with the search for truth, the marketplace of ideas, or democratic self-government. They may not interfere as much as does, say, the threat of prison for saying certain things; but they may interfere more than some more modest threats imposed by the government.
Now of course protecting freedom of speech from private entities raises its own complicated sets of problems. Some such protections can violate others' free speech rights (e.g., if you extend free speech to include a right to march in someone else's parade or publish in someone else's newspaper). They can violate others' religious freedom rights (e.g., if you bar churches from excommunicating members based on their speech).
And they can limit others' property rights, or others' rights to choose whom to associate with; even if those limitations aren't unconstitutional, they can still be wrong. This is why many libertarians, who strongly value property rights, resist creating such speech-protective but private-party-restricting rules, to the extent those rules protect against firing, expulsion, removal from property, and the like (as opposed to protecting against private violence or vandalism).
But such protections are nonetheless protections for the freedom of speech. To offer some examples,
- About half of Americans live in jurisdictions that in some measure protect private employees from being fired by their employers for political speech (sometimes just speech related to elections and sometimes speech more broadly). This helps protect political debate, I think, though of course at some cost.
- California law protects private university and high school students from being disciplined for their speech; and there are similar free speech rules promised by many private universities in other states.
- A few states (California, New Jersey, and Pennsylvania) protect public speech at large private shopping malls.
- Regulations of various public utilities and common carriers, which require them to generally accept all paying customers, incidentally protect people and groups from losing important services because of their speech.
I'm not sure all these laws are sound. But they do protect free speech, whether we think they're on balance justified or not. If that's a position usually associated more with liberals than with conservatives or libertarians, well then the liberals are right about that (though again one can dispute whether those free speech protections are sound, given the countervailing private property rights and associational rights that we might value).
And even beyond legal rules or contractual obligations, some kinds of restrictions interfere with free speech. If, for instance, an important professional organization threatens to expel members who are viewed (often incorrectly) as Communists, racists, and the like, that can deter public debate and political participation by its members.
Perhaps the organization should have the legal right to do that. Indeed, perhaps in some situations the organization's actions might be justifiable—maybe what constitutes improper interference with speech might be different for private organizations than for the government, and might differ among private organizations. But in other situations the organization might rightly be faulted for improperly interfering with the speech of its members, and undermining democratic self-government.
So remember the state action doctrine when it comes to the Free Speech Clause; but remember that there's more to actual freedom of speech than just the freedom from government retaliation.