Spoiler - they can't

It can't

The courts have been making those calls since before there were any amendments, and reconciling free speech with people's right not to be libeled or slandered through all of our history.

https://www.mtsu.edu/first-amendment/article/997/libel-and-slander#

That's the courts, not the other branches of government that should rightly stay the hell out!

But the courts are part of the government. And yes, separation of powers is vital to democracy.

No sorry. Everyone can say what they want, they are paying damages for the loss of reputation not for saying something.

That is the court reacting to the adverse affects possible with free speech (after the fact), it isn't the government preemptively censoring people (pre-crime).

There's a huge difference.