And that's not how I or fillippone see it; it's the way the protocol sees it. If you have a private key, you can sign messages with it. You're, therefore, the signer and, ultimately, the legitimate owner of that key.
I would have expected nullius to understand this. The protocol is much more important than anything else including ethics. Ethics can't be enforced.
If someone knows my private keys, I totally assume I lose my funds.