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

No freedom is absolute.

Fraud

HIPAA violations

Towards topological quantum batteries: Theoretical framework addresses two long-standing challenges - Phys.org

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.

Insurrection

The Webb telescope found something exceedingly rare around a dying star - Mashable

Revenge porn

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.

Am I the unique Gen Z if I dislike TikTok and prefer the 2000s technology trends like retro consoles, CRTs, and CD/DVDs?

Freedom of speech does not apply to:

Conspiracy

Insider trading

What do you think is the #1 cause of why relationships nowadays don't seem to last long?

And much, much more.

Threats of violence

Revealing classified information

Which scene is considered the most difficult to watch in each of Quentin Tarantino's movies?

Trade secrets

Child pornography

Perjury

Earth’s oldest living creature unearthed—dating back 700 million years - The Brighter Side of News

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.

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.