The law probably requires them to do so. Meanwhile, in the non-governmental real world, nobody is going to agree to direct deposit if an accidental extra zero on your paycheck means they have to sue you to recover it.
I've been having my salary direct-deposited with a variety of banks and employers for almost twenty years now, and not once have I had a problem where they had to go and recover money from me. You got hit by lightning, basically - it happens, and I'm sorry it happened to you, but let's not get maudlin.
Yes, the rules are supposed to cover only those sorts of situations -- the extra zero, the duplicate, etc. My warning is that in reality, the employer can just take the money for whatever reason he chooses. The employer is protected by exposing the employee to risk. That's not fair, imo. There should be REAL punishment to an employer who breaks the rules.