What is the point in having a contract which one party doesn't read or understand? The point of the contract is to confirm agreement, but how can you have agreement if one side doesn't even know to what they're agreeing?
It's a long established rule of contract law that if you sign it you agree to it, with a couple of narrow exceptions. Technically people are free to read it and get legal advice on it, of course nobody does!
Fortunately, many jurisdictions have limitations on what can go into a consumer contracts as they know about these issues. The law helps restrict what is valid in the T&Cs and what is not, it's not perfect but it's better than nothing.