Being a victim of fraud is not "voluntary" in any meaningful way.
Voluntary or not is a red herring. The word this discussion is looking for is authorized.
The transfer was authorized by the account holder. They were defrauded. But when they made the transfer, then intended to do so. (The situation is murkier with credit card transactions, at least in America, because they chose to accept a role in dispute resolution.)
The $625mm drained out of Axie's account wasn't authorized by Sky Mavis. That's a different type of fraud than being ripped off.
But that's a different case than money being "drained" from an account by someone else.
And that shows the difference in how each is protected.
If A has a TV, B steals the TV and sells it to C, who sells it to D...then the TV is still returned to A, and D is out of luck.
It protects again bank failure. If the one's assets are drained from the bank, as long as the bank has not failed, it will have to make the account holder whole.
That's why a company would be stupid to hold $200M at Podunk Bank of Littletown, KS but is perfectly fine to hold it in a DDA account at Bank of America, Citi or Chase
But even then, if you store $650 MM in a Bank of America account, that money is protected against being stolen by BOA's anti-fraud software, laws, the trillions of dollars of assets BOA has.