If freedom of speech is absolute, how come it's not applied for private spaces and for the Internet?

No freedom is absolute.

Trade secrets

If you’re wondering why free speech doesn’t apply to the internet, it’s because you have no right to use other people’s stuff for free.

How do I express sarcasm in non-dialogue text when writing a fiction novel?

You have freedom of speech. If I loan you my computer, I can tell you not to use it for certain things, because it’s mine, you have no right to use it, and if I give you permission to use it I can tell you what you can and can’t do with it.

Insider trading

Perjury

What are some very specific groups of people you just cannot stand?

Child pornography

You have freedom to travel. If I loan you my car, I can tell you not to take it out of town, because it’s mine, you have no right to use it, and if I give you permission to use it I can tell you what you can and can’t do with it.

HIPAA violations

Bettor banned for heckling Olympic star Thomas - ESPN

Fraud

That’s what it is. You have no right to use other people’s stuff. If people let you use their stuff, they can tell you how you can use it, and they can tell you to stop using it any time they want.

Freedom of speech does not apply to:

While emptying a house, have you ever seen something in it that blew your mind?

Insurrection

Threats of violence

And much, much more.

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False advertising

Revenge porn

Terroristic threats

Secret Characters in Elden Ring Nightreign: How to Unlock the Revenant and Duchess - CNET

Conspiracy

Revealing classified information