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.

No freedom is absolute.

Freedom of speech does not apply to:

How is it not psychopathic to use someone for sex, even if they agree?

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.

Trade secrets

Conspiracy

Why do I have the impression that almost all questions about advertising the flat Earth theory come from people who don't believe in a flat Earth themselves and are just provoking?

Threats of violence

False advertising

HIPAA violations

Is Trump the greatest spiritual leader since Jesus?

Insurrection

Revealing classified information

Perjury

Is Tinder the best dating app?

And much, much more.

Fraud

Terroristic threats

If there exists a “New York of Australia”, is it Sydney or Melbourne?

Child pornography

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

What do you wear when you are alone at home?

Revenge porn

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.