Freezing coins in this case is not some rulers confiscating some users' coins but all actual users refusal to sponsor a Quantum frenzy.
You are painting a picture of somebody imposing a change on people that would destroy their property entirely.
A more benevolent interpretation is that all those that still have access to their coins agree to make sure the coins that were lost stay lost instead of coming back from the grave to haunt us in form of aggressive inflation thus destroying all users' property partly.
I'm firmly in support of any scheme that makes sure that quantum computers won't be used to break Bitcoin's public key cryptography and only fear we shoot our own feet too early ... or too late.