In my opinion…
Decentralization is not an end in and of itself but a means to eliminate the risks that come with a centralized system. Specifically, decentralization provides the means to protect against centralized control that would otherwise threaten an individual’s right to control his or her own assets. Decentralized blockchain systems have value as a tool because they can protect private property rights in a way that was not previously possible. However, to the extent these new systems introduce new ways that prevent owners from accessing that which they own, they fail to be useful.
Also, the blockchain is not immutable, nor would it be of any use if it were. The current state of the blockchain mutates with every transaction. However, client logic is designed to prevent unauthorized changes. An account owner authorizes the client application to perform actions on his or her behalf by signing transactions, thus proving their ownership and intent to mutate their portion of the blockchain state. To be clear, owners grant permission to the client to modify the blockchain state on their behalf, not the other way around.
How, then, should a decentralized system behave when users are prevented from controlling the assets they own?
Proof of ownership and intent are of primary importance. If ownership and intent can be demonstrated (e.g. through signed messages, data on chain), what grounds do we have to prevent owners from controlling their assets? Why should we sacrifice the ends in support of the means?