Which is why societies have come up with a far better method: collectively decide (or collectively choose people to decide) on reasonable limits for certain types of transactions.
My German law professor used to say that she never read ToS. Because under the country's law, they are either reasonable or unenforceable.
Such laws have nothing to with censorship. If you really need your users private messages, you just have to more explicitly present them with the choice, and respect their decision to say no without unreasonably denying them service.
The US has far more lenient standards for such one-sided contracts, but the basic principle is obviously the same: If Facebook were to add a paragraph giving them ownership of your house somewhere deep in the ToS, they wouldn't stand a chance in a court of law.