I think the disconnect is that they think you can encumber a system using power as a control instead of logic

But the problem is that bitcoin necessarily has to use the logic of private key management to lay claim to *previously earned* proof of work

It would have to be pure proof of work only without bitcoin to decouple the functions. It is still a foolish proposal to me. Do you really wanna encumber an action solely by hoping you have the most PoW muscle? I can’t think of a scenario where it makes sense stand-alone.

POW = good Sybil resistance

Good Key management = good security

They’re loosely related but separate.