But it is complicated, no? Even if you click you agree, if the you thought you were agreeing to one thing but actually agreed to another because they buried the lede, “I didn’t read it” is a reasonable defense.

Why would you claim the false "I didn't read it" ahead of the true "I read it but understood it differently"? The latter allows for adding the fault shifting claim "because the other party wrote it deceptively", while "intentionally didn't read" makes it much harder to blame the other guy.

It just won’t fly in court. Full stop. There are perhaps other defenses to be raised, like unconscionable terms, but not that one.

It really depends on the term they're trying to rely on. We have the "red hand rule" in England and Wales that means that unusual and onerous terms will not be incorporated unless it can be expressly shown they were fairly brought to the parties attention.