You're allowed to be ignorant of trespassing statutes too. But you can still be kicked out of someone's business.

That's quite different. In criminal law, ignorance of the law is explicitly not a defence.

In contract law, you have to sign up to the contract. One side can not just assert that the other side agreed to some terms unless they can show that this happened.

Browserwrap agreements don't require the user to click on anything though.

First time you go to YouTube (at least in Europe), it shows a cookie banner containing a link to the ToS. (Try it from a private mode browser window.)