“To a POINT…If the contract makes a statement that contradicts LAW…then that part of the contract is not enforceable. Many states have laws stating that a person has the right to get out of any contract within 72 hours after signing the contract. If the contract has a statement that says that you can’t back out of the contract within the 72 hours…then that part of the contract is unenforceable.”
Looks like you may have missed the part in bold:
"That last bit is correct, but only because you picked an example that’s not legal, and something that’s illegal is not binding. That’s the first day of Contracts 101 or whatever they call it these days.
Other than that, the whole point of a contract is that it does mean what it says"