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

No freedom is absolute.

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.

Insurrection

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HIPAA violations

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.

Fraud

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Revealing classified information

Freedom of speech does not apply to:

Revenge porn

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False advertising

Child pornography

Threats of violence

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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.

And much, much more.

Trade secrets

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Perjury

Insider trading

Conspiracy

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Terroristic threats

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.