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

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.

Terroristic threats

Revealing classified information

Does the West have a defense against China's PL17 air-air missile?

Fraud

And much, much more.

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.

Why do people hate on Serena (anime character)? What did she ever do to anyone except be a good friend to Ash Ketchum and an awesome trainer herself?

Child pornography

No freedom is absolute.

Perjury

Accidental find in planetarium show could shift scientists’ understanding of our solar system - CNN

Conspiracy

HIPAA violations

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.

Why are people becoming increasingly hostile to pro-lifers? I am pro-life.

Revenge porn

Threats of violence

Trade secrets

Hurricane Sandy May Have Affected The Brains of Unborn Children - ScienceAlert

False advertising

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.

Insider trading

‘Superman’ Final Trailer Shows David Corenswet “Doing Important Stuff” - The Hollywood Reporter

Freedom of speech does not apply to:

Insurrection