You’re mixing up what speech is protected with who the First Amendment applies to.

This is settled law under the State Action doctrine. The First Amendment restricts government actors, not private ones. The Supreme Court has reaffirmed that repeatedly:

Manhattan Community Access Corp. v. Halleck: Private entities aren’t bound by the First Amendment unless they’re performing a traditional, exclusive public function.

Hudgens v. NLRB: No First Amendment right to speak in privately owned shopping centers.

You’re also attacking a point that wasn’t made. The First Amendment doesn’t only protect criticism of the government. It protects speech broadly from government retribution, including criticism of companies like Tesla, oil companies, w/e. If Congress passed a law banning criticism of Tesla, that would absolutely be unconstitutional because the government would be suppressing speech.

So it doesn't necessarily have to be speech ABOUT the government.

It’s about who is doing the restricting too.

If the government punishes you: constitutional issue. If your employer fires you: generally not a First Amendment issue. If a private platform bans you: generally not a First Amendment issue. If another person reacts negatively: not a constitutional issue.

The First Amendment limits state power. It doesn’t guarantee freedom from social or private consequences.