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.

Trade secrets

Insider trading

Ford Stock Rises After Strong May Sales. The Pain Is Coming. - Barron's

Freedom of speech does not apply to:

No freedom is absolute.

Child pornography

Samsung is giving these Galaxy phones a big One UI upgrade - here's which models qualify - ZDNET

HIPAA violations

Fraud

Threats of violence

Corbin Burnes To Undergo Tommy John Surgery - MLB Trade Rumors

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.

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.

Insurrection

The First At-Home Cervical Cancer Screening Device Was Approved by the FDA, Set to Roll Out This Year - Good News Network

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.

Conspiracy

Why should we share our wife with others?

Perjury

False advertising

Terroristic threats

Trump administration prepares to ease big bank rules - Politico

Revealing classified information

Revenge porn