I would assume "s/employment contracts/employment agreements/" is closer to what was meant.

They are contracts though, we just agree to miserable terms.

They aren’t contracts in at-will employment states

The at-will clause in your employment contract is one of MANY terms with rather far-reaching legal implications.

But for example you almost certainly have a moonlighting clause with specific rules. You have invention disclosure and ownership with rules. These represent binding contracts between you and your employer, often with rules around conflict resolution that are also legally binding.

Most jobs require the employee to sign a contract. It's just not a contract that gives them any assurance of keeping their job.

I took that not to mean literal contracts, but rather a "contract of expectations"—we pay you X, in return you do Y (where in this case Y is "work longer hours" and such).

If you work full time you sign an agreement which contains contractual obligations. The fact that employment is 'at-will' doesn't really change this fact or characterization.